some words about beach

A beach is a geological landform along the shoreline of a body of water. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles, or cobble. The particles of which the beach is composed can sometimes instead have biological origins, such as shell fragments or coralline algae fragments.

Beaches often occur along coastal areas, where wave or current action deposits and reworks sediments.

Although the seashore is most commonly associated with the word "beach", beaches are not only found by the ocean: beaches also occur at the margin of the land along lakes and rivers where sediments are reworked or deposited.

The term 'beach' may refer to:

• small systems in which the rock material moves onshore, offshore, or alongshore by the forces of waves and currents; or
• geological units of considerable size.

The former are described in detail below; the larger geological units are discussed elsewhere under bars.

There are several conspicuous parts to a beach, all of which relate to the processes that form and shape it. The part mostly above water (depending upon tide), and more or less actively influenced by the waves at some point in the tide, is termed the beach berm. The berm is the deposit of material comprising the active shoreline. The berm has a crest (top) and a face — the latter being the slope leading down towards the water from the crest. At the very bottom of the face, there may be a trough, and further seaward one or more longshore bars: slightly raised, underwater embankments formed where the waves first start to break.

The sand deposit may extend well inland from the berm crest, where there may be evidence of one or more older crests (the storm beach) resulting from very large storm waves and beyond the influence of the normal waves. At some point the influence of the waves (even storm waves) on the material comprising the beach stops, and if the particles are small enough (sand size or smaller), winds shape the feature. Where wind is the force distributing the grains inland, the deposit behind the beach becomes a dune.

These geomorphic features compose what is called the beach profile. The beach profile changes seasonally due to the change in wave energy experienced during summer and winter months. The beach profile is higher during the summer due to the gentle wave action during this season. The lower energy waves deposit sediment on the beach berm and dune, adding to the beach profile. Conversely, the beach profile is lower in the winter due to the increased wave energy associated with storms. Higher energy waves erode sediment from the beach berm and dune, and deposit it off shore, forming longshore bars. The removal of sediment from the beach berm and dune decreases the beach profile.

The line between beach and dune is difficult to define in the field. Over any significant period of time, sand is always being exchanged between them. The drift line (the high point of material deposited by waves) is one potential demarcation. This would be the point at which significant wind movement of sand could occur, since the normal waves do not wet the sand beyond this area. However, the drift line is likely to move inland under assault by storm waves.

Beach formation

Beaches are deposition landforms, and are the result of wave action by which waves or currents move sand or other loose sediments of which the beach is made as these particles are held in suspension. Alternatively, sand may be moved by saltation (a bouncing movement of large particles). Beach materials come from erosion of rocks offshore, as well as from headland erosion and slumping producing deposits of scree. Some of the whitest sand in the world, along Florida's Emerald Coast, comes from the erosion of quartz in the Appalachian Mountains. A coral reef offshore is a significant source of sand particles.

The shape of a beach depends on whether or not the waves are constructive or destructive, and whether the material is sand or shingle. Constructive waves move material up the beach while destructive waves move the material down the beach. On sandy beaches, the backwash of the waves removes material forming a gently sloping beach. On shingle beaches the swash is dissipated because the large particle size allows percolation, so the backwash is not very powerful, and the beach remains steep. Cusps and horns form where incoming waves divide, depositing sand as horns and scouring out sand to form cusps. This forms the uneven face on some sand shorelines.

There are several beaches which are claimed to be the "World's longest", including Cox's Bazar, Bangladesh (120 km), Fraser Island beach, 90 Mile Beach in Australia and 90 Mile Beach in New Zealand (88 km) and Long Beach, Washington (which is about 40 km). Wasaga Beach, Ontario on Georgian Bay claims to have the world's longest freshwater beach. But the longest beach in the world is in fact Praia do Cassino, a 240km long beach located in southern Brazil, near the border with Uruguay.

Beaches and recreation

In the Victorian era, many popular beach resorts were equipped with bathing machines because even the all-covering beachwear of the period was considered immodest. This social standard still prevails in many Muslim countries. At the other end of the spectrum are topfree beaches and nude beaches where clothing is optional or not allowed. In most countries social norms are significantly different on a beach in hot weather, compared to adjacent areas where similar behaviour might not be tolerated. For example, undressing down to swimwear, showering in public, women exposing their breasts and lying with legs apart, etc.

A walk along the beach is also popular, including a long walk in the case of a long beach, for example from one seaside resort to the next. When and where the sand is not too hot, people often walk barefoot on the beach, because of the pleasant feeling of sand on their soles and between their toes. The best beach walking areas typically are near the shoreline, where the sand is wet and more comfortable to walk in. A person will also enjoy walking with their bare feet in the water.

In more than thirty countries in Europe, South Africa, New Zealand, Canada, Costa Rica, South America and the Caribbean, the best recreational beaches are awarded Blue Flag status, based on such criteria as water quality and safety provision. Subsequent loss of this status can have a severe effect on tourism revenues.

Due to intense use by the expanding human population, beaches are often dumping grounds for waste and litter, necessitating the use of beach cleaners and other cleanup projects. More significantly, many beaches are a discharge zone for untreated sewage in most underdeveloped countries; even in developed countries beach closure is an occasional circumstance due to sanitary sewer overflow. In these cases of marine discharge, waterborne disease from fecal pathogens and contamination of certain marine species is a frequent outcome.

some words about mountain

A mountain is a landform that extends above the surrounding terrain in a limited area, with a peak. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit. Mountains cover 64% of Asia, 36% of North America, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous. 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.^[1][2]

The adjective montane is used to describe mountainous areas and things associated with them. Orology is its specialized field of studies, though the term is mostly replaced by "mountain studies". (Not to be confused with horology

Some authorities define a mountain as a peak with a topographic prominence over a defined value: for example, according to the Britannica Student Encyclopedia, the term "generally refers to rises over 2,000 feet (610 m)" The Encyclopædia Britannica, on the other hand, does not prescribe any height, merely stating that "the term has no standardized geological meaning"

In the United States

In the United States, the U.S. Board on Geographic Names lists hundreds of landscape features under 1,000 feet (305 m) (some as low as 100 feet) named as "mountains." This is true for all parts of the United States, including the west coast where such lofty ranges as the Cascade Mountains dominate. And yet the Board does not attempt to distinguish between such features as mountains, hills, or other prominences, and simply categorizes all of them as summit, regardless of what they are called or how high they are. However, the Board does list and categorize such low mountain ranges as the Mount Tom Range (with a high point of 1,200 feet; 366 m) as range

The height of a mountain is measured as the elevation of its summit above mean sea level. The Himalayas average 5 km above sea level, while the Andes average 4 km. The highest mountain on land is Everest, 8,848 metres (29,030 ft) in the Himalayas.

Other definitions of height are possible. The peak that is farthest from the center of the Earth is Chimborazo in Ecuador. At 6,267 metres (20,560 ft) above sea level it is not even the tallest peak in the Andes, but because Chimborazo is very close to the equator and the Earth bulges at the equator, it is 2,150 metres (7,100 ft) further away from the Earth's center than Everest.^[5] The peak that rises farthest from its base is Mauna Kea on Hawaii, whose peak is 10,200 metres (33,500 ft) above its base on the floor of the Pacific Ocean.^[6] Mount Lamlam on Guam also lays claim to the tallest mountain as measured from it base. Although its peak is only 406 metres (1,330 ft) above sea level, it measures 11,530 metres (37,830 ft) to its base at the bottom of the Marianas Trench.^[7]

Even though Everest is the highest mountain on Earth today, there have been much taller mountains in the past. During the Precambrian era, the Canadian Shield once had mountains 12,000 m (39,370 ft)^[8] in height that are now eroded down into rolling hills. These formed by the collision of tectonic plates much like the Himalaya and the Rocky Mountains.

At 26 kilometres (85,000 ft) (Fraknoi et al., 2004), the tallest known mountain in the solar system is Olympus Mons, located on Mars and is an ancient volcano. Volcanoes have been known to erupt on other planets and moons in our solar system and some of them erupt ice instead of lava (see Cryovolcano). Several years ago, the Hale telescope recorded the first known images of a volcano erupting on a moon in our solar system

Characteristics

High mountains, and mountains located closer to the Earth's poles, have elevations that exist in colder layers of the atmosphere. They are consequently often subject to glaciation and erosion through frost action. Such processes produce the popularly recognizable mountain peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan. Sufficiently tall mountains have very different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes. The flora and fauna found in these zones tend to become isolated since the conditions above and below a particular zone will be inhospitable to those organisms. These isolated ecological systems are known as sky islands and/or microclimates. Tree forests are forests on mountain sides which attract moisture from the trees, creating a unique ecosystem. Very tall mountains may be covered in ice or snow.

Mountains are colder than lower ground, because the Sun heats Earth from the ground up. The Sun's radiation travels through the atmosphere to the ground, where Earth absorbs the heat. Air closest to the Earth's surface is, in general, warmest (see lapse rate for details). Air as high as a mountain is poorly warmed and, therefore, cold.^[9] Air temperature normally drops 1 to 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) for each 300 meters (1000 feet) of altitude.

Mountains are generally less preferable for human habitation than lowlands; the weather is often harsher, and there is little level ground suitable for agriculture. At very high altitudes, there is less oxygen in the air and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3,500 meters (11,483 feet).

A number of mountains and mountain ranges of the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use of any sort at all. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility ranges from mountain to mountain; height, steepness, latitude, terrain, weather, and the presence or lack thereof of roads, lifts, or tramways are all factors that affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities typically enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts.

Types of mountains

Mountains can be characterized in several ways. Some mountains are volcanoes and can be characterized by the type of lava and eruptive history. Other mountains are shaped by glacial processes and can be characterized by their glaciated features. Still others are typified by the faulting and folding of the Earth's crust, or by the collision of continental plates via plate tectonics (the Himalayas, for instance). Shape and placement within the overall landscape also define mountains and mountainous structures (such as butte and monadnock). Finally, many mountains can be characterized by the type of rock that make up their composition. More information on mountain types can be found in List of mountain types.

Geology

A mountain is usually produced by the movement of lithospheric plates, either orogenic movement or epeirogenic movement. The compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, a mountain. The absolute heights of features termed mountains and hills vary greatly according to an area's terrain. The major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Two types of mountain are formed depending on how the rock reacts to the tectonic forces – block mountains or fold mountains.

The compressional forces in continental collisions may cause the compressed region to thicken, so the upper surface is forced upward. In order to balance the weight of the earth surface, much of the compressed rock is forced downward, producing deep "mountain roots" [see the Book of "Earth", Press and Siever page.413]. These roots are deeply embedded in the ground, thus, a mountain have a shape like peg [See Anatomy of the Earth, Cailleus page.220]. Mountains therefore form downward as well as upward (see isostasy). However, in some continental collisions part of one continent may simply override part of the others, crumpling in the process.

Some isolated mountains were produced by volcanoes, including many apparently small islands that reach a great height above the ocean floor.

Block mountains are created when large areas are widely broken up by faults creating large vertical displacements. This occurrence is fairly common. The uplifted blocks are block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley. These areas often occur when the regional stress is extensional and the crust is thinned.

The mid-ocean ridges are often referred to as undersea mountain ranges due to their bathymetric prominence.

Where rock does not fault it folds, either symmetrically or asymmetrically. The upfolds are anticlines and the downfolds are synclines; in asymmetric folding there may also be recumbent and overturned folds. The Jura mountains are an example of folding. Over time, erosion can bring about an inversion of relief: the soft upthrust rock is worn away so the anticlines are actually lower than the tougher, more compressed rock of the synclines.

Samsung G800 Review

The world's first phone to offer a 5 megapixel camera with optical zoom, the G800 sets the benchmark for camera phones. It's also a beautifully designed slide phone that's fully equipped with an MP3 player, FM radio, accelerated 3G (HSDPA), 160 Mbytes of internal memory plus a memory card slot, and Bluetooth wireless connectivity.
Samsung have taken the phone world by storm by announcing at the end of October 2007 the release of the world's first 5 megapixel camera with optical zoom in a mobile phone. If the plan was to draw attention away from the release of the iPhone, then this has certainly done the trick! Launching in the UK on 12th November 2007, the G800 will be the most advanced camera phone in the world.

Samsung have pulled off both a technological and design marvel with the G800. Its closest rivals are the Nokia N95 and Sony Ericsson K850i, which both have 5 megapixel cameras. But the G800 trumps them with the introduction of a 3x optical zoom. An optical zoom is common in dedicated digital cameras, but is very rare in camera phones, because of size constraints. It enables the camera lens to zoom into a scene retaining the full 5 megapixel resolution. By contrast, the digital zoom used in the N95 and K850i (and other camera phones) loses resolution when zooming. The G800 is also the first Samsung phone to have a real xenon flash instead of the weaker LCD flashes usually seen in camera phones. Samsung are one of the key manufacturers of digital cameras, and they have clearly used their expertise in the field to create a world beater with the G800. Other new features that have been imported from the digital camera world are face detection, and Wide Dynamic Range (WDR). Face detection detects the presence of a face in a subject and adjusts the exposure and focus to optimise the appearance of the face.

However, we have to point out that judging from our user reviews, a lot of people have trouble getting good quality pictures from the G800, particularly in low lighting conditions. How can we explain this? One issue that Samsung really need to sort out is to make the highest resolution the default setting on their camera phones, because the default setting is low resolution. If you don't change the setting, you're effectively using a VGA camera! Another problem is that the G800 incorporates a lot of camera features (anti-shake, face detection, WDR, ISO settings, etc) and this means lots of settings to worry about and lots of things potentially to go wrong. So if you're looking for a point-and-shoot camera, look elsewhere. We've decided to deduct one point from our rating for this reason. Many of these comments also apply to the Sony Ericsson K850i, which has also generated a lot of complaints from our users about the camera quality - again in low lighting conditions. Our conclusion is that phone manufacturers should concentrate on making their camera phones as simple to use as possible, as juggling settings isn't really what you want to be doing with a camera phone. But for camera enthusiasts, we still rate the G800 as one of the top 3 camera phones of 2008 (the Nokia N95 and Sony Ericsson K850i being the other two.)
As you can see from the photos, not only is this the highest spec camera phone, but it's also a sexy-looking slider that beats its rivals hands down in terms of looks. It may not be the slimmest phone around, but it's certainly more compact than the N95 and is a good size for two-handed camera use. Turn the phone over and the back is like a real digital camera, complete with a sliding lens cover. The secret to making such a compact device is that the optical zoom is an inner zoom, where the lens does not extend outside the body of the phone.

The G800 also has a new camera Graphical User Interface which provides the same environment as a digital camera when using the camera function on the phone. An On Screen Display shows various camera indicators in a horizontal preview mode. The large 2.4 inch LCD display is ideal for viewing images. There's a built-in picture editor, and direct printing to a Pictbridge-compatible printer is supported. High quality video recording is also available, and a built-in video editor is provided too.

As well as the photographic functions, the G800 incorporates all of the features seen in previous high-end Samsung phones. The music player supports all major formats (MP3, AAC, AAC+, 3-AAC+, WMA formats) and wireless Bluetooth stereo headsets. A stereo FM radio is also included. The G800 is superbly equipped with memory too: 160 Mbytes of internal memory is sufficient to hold around 40 music tracks, and you can expand this with a microSD memory card.

Connectivity is excellent too, with support for Bluetooth 2.0, USB 2.0 and TV-Out. Interestingly the G800 is a 3G phone too, in fact it supports the latest high-speed 3G nicknamed 3.5G. Specifically, the 3G implementation is 7.2 Mbps HSDPA, which offers download equivalent to broadband speeds. A web browser is built-in, and the phone can handle RSS feeds and mobile blogging. Email with support for attachments is available and a document viewer can view most common file formats (Word, Excel, Powerpoint & PDF).

The G800 is an outstanding phone. After a year in which Samsung appeared to stumble, at the close of 2007 it has launched a product that sets the standards in camera phone for the year ahead.

Share this page on Del.icio.us

Features of the Samsung G800 include:

* 5 megapixel camera phone with 3x optical zoom, autofocus and Xenon flash
* Video camera with built-in video editing
* Display: TFT, 256k colours, 320 x 240 pixels (2.4 inches)
* MP3 player (MP3, AAC, AAC+, 3-AAC+, WMA formats)
* Stereo FM radio
* Speakerphone
* Messaging: SMS, MMS, email (POP3 / SMTP / IMAP4)
* Document viewer
* Java games (Java MIDP 2.0)
* Personal organiser functions
* Offline mode
* WAP 2.0, GPRS Class 10, EDGE
* High Speed Downlink Packet Access (HSDPA, 7.2 Mbps) - 3.5G
* xHTML web browser, RSS feeds, mobile blogging
* Memory: 160 Mbytes plus microSD memory card slot
* Connectivity: Bluetooth 2.0, USB 2.0, TV-Out
* Triband (GSM 900 / GSM 1800 / GSM 1900) plus 3G
* Size: 102 x 52 x 19 mm
* Weight: 134g

Samsung Omnia Review

The Samsung Omnia is the hottest phone of 2008. It's a touchscreen smartphone and, unlike the iPhone, it does everything that a high-spec phone ought to do. The Omnia has everything: a 5 megapixel camera, 3G video calling, a music player & FM radio, fast web browsing, the most memory ever seen on a mobile phone, and it connects to any device you can think of via Bluetooth, USB or Wi-Fi.
Best buy: *Free* with half-price line rental from Dialaphone (Black) or Dialaphone (White) or Mobiles.co.uk.

Wow! While Apple have been hyping their iPhone 3G for the best part of a year, the Samsung Omnia has come from nowhere, and is the phone that the iPhone should have been. Whereas the iPhone misses out on all kinds of essential features, the Omnia does almost everything that you could want from a phone, and does it very well.

The Omnia looks super-cool too. The sleek platinum finish and the slim body give the phone wow! factor, even before you start using it.

Samsung have been churning out touchscreen phones since the beginning of 2008. First the Armani, then the Nerva, then the Tocco, each time refining the design and getting closer to the perfect phone. Now the Omnia looks like it could be "the one". Samsung's touchscreen user interface has improved a little with each release, although we criticised the Tocco for having a smaller screen. There is no problem with the Omnia however, which has a massive WQVGA 3.2 inch screen - that's even bigger than the LG Viewty and only slightly smaller than the iPhone 3G. The TouchWiz user interface is an excellent implementation of a touchscreen phone. TouchWiz uses a variety of intuitive touch controls, e.g. tap, sweep, drag and drop operations as well as an on-screen qwerty keyboard. The screen uses tactile feedback to help you feel your way around the menus and controls, and even hard-core texters should be happy with the result. The iPhone may have paved the way in touchscreen UI design, but Samsung have followed very well.

The Omnia is a smartphone running Windows Mobile 6.1. This has a number of advantages. Firstly, the user interface will be familiar to PC users, even including a mobile version of Internet Explorer for web browsing. Secondly, the system enables convenient access to Office documents such as PowerPoint, Excel and Word (for editing as well as viewing). Thirdly, you can download third-party applications and install them on your phone. The phone comes pre-installed with very comprehensive personal organiser functions. The downside is that all smartphones have a tendency to be slow and buggy. Nokia N95 users will be familiar with this!

Let's take a look at the multimedia capabilities of the phone now. Summarising in three words: it does everything! Really! Let's consider the spec: A 5 megapixel camera with face-detection autofocus, smile detection (takes a shot when everyone is smiling), auto-panorama, LED flash and digital zoom. It may not have the optical zoom of the Samsung G800, the optics of the Nokia N95, or the xenon flash of the Sony Ericsson K800i, but we would rate it in the top 10 of current camera phones. In any case, it walks all over the feeble camera in the iPhone 3G. The camera can be used as a business card reader too. It also has an excellent video camera (with image stabilisation), and the video playback capability includes Divx support. Of course it's a 3G phone with video calling too. The music player is very good and supports nearly all formats, and an FM radio is included too. Web browsing is also an enjoyable experience on the Omnia, with fast HSDPA downloads, the large touchscreen, and advanced Opera browser all working together to provide a good experience. The Omnia also comes with GPS navigation built in.

One of the outstanding features of the Omnia is the absolutely huge memory that it supports. Available in a choice of 8 or 16 Gbytes, it also has a microSD memory card slot, enabling an additional 8 Gbytes to be added. This means that you can store a huge amount of music or video (around 8,000 songs or 23 DVD-quality films) and you can even store up to 120 Mbytes worth of text or MMS messages.

The battery life is very good too, which is quite a surprise for a touchscreen phone with so much functionality. We doubt Samsung's official figures of 450 hours standby however.

Connectivity is unbeatable, with a choice of Bluetooth, USB and Wi-Fi.

Really, the Omnia is an amazing phone, and it's no surprise that it's moved right to the top of the best seller charts at launch. Touchscreen phones are the hottest product in 2008, and the Omnia is arguably the best so far. If you fancied the new iPhone or the LG Viewty, you should really be looking at the Omnia instead. The only issue is the Windows Mobile operating system, which is admittedly very powerful, but is not the most stable operating system ever invented. But even so, this is definitely a 5 star phone!!!

Some Words of Cancer

Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize. Most cancers form a tumor but some, like leukemia, do not. The branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology.

Cancer may affect people at all ages, even fetuses, but the risk for most varieties increases with age.^[1] Cancer causes about 13% of all deaths.^[2] According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007.^[3] Cancers can affect all animals.

Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. The heritability of cancers are usually affected by complex interactions between carcinogens and the host's genome. New aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs are increasingly recognized as important.

Genetic abnormalities found in cancer typically affect two general classes of genes. Cancer-promoting oncogenes are typically activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are then inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.

Diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. Most cancers can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.

Classification

Cancer is generally classified according to the tissue from which the cancerous cells originate, the primary tumor, as well as the normal cell type they most resemble. These are location and histology, respectively.

Nomenclature

The following closely related terms may be used to designate abnormal growths:

• Tumor or tumour: originally, it meant any abnormal swelling, lump or mass. In current English, however, the word tumor has become synonymous with neoplasm, specifically solid neoplasm. Note that some neoplasms, such as leukemia, do not form tumors.
• Neoplasm: the scientific term to describe an abnormal proliferation of genetically altered cells. Neoplasms can be benign or malignant:
  • Malignant neoplasm or malignant tumor: synonymous with cancer.
  • Benign neoplasm or benign tumor: a tumor (solid neoplasm) that stops growing by itself, does not invade other tissues and does not form metastases.
• Invasive tumor is another synonym of cancer. The name refers to invasion of surrounding tissues.
• Pre-malignancy, pre-cancer or non-invasive tumor: A neoplasm that is not invasive but has the potential to progress to cancer (become invasive) if left untreated. These lesions are, in order of increasing potential for cancer, atypia, dysplasia and carcinoma in situ.

The following terms can be used to describe a cancer:

• Screening: a test done on healthy people to detect tumors before they become apparent. A mammogram is a screening test.
• Diagnosis: the confirmation of the cancerous nature of a lump. This usually requires a biopsy or removal of the tumor by surgery, followed by examination by a pathologist.
• Surgical excision: the removal of a tumor by a surgeon.
  • Surgical margins: the evaluation by a pathologist of the edges of the tissue removed by the surgeon to determine if the tumor was removed completely ("negative margins") or if tumor was left behind ("positive margins").
• Grade: a number (usually on a scale of 3) established by a pathologist to describe the degree of resemblance of the tumor to the surrounding benign tissue.
• Stage: a number (usually on a scale of 4) established by the oncologist to describe the degree of invasion of the body by the tumor.
• Recurrence: new tumors that appear at the site of the original tumor after surgery.
• Metastasis: new tumors that appear far from the original tumor.
• Transformation: the concept that a low-grade tumor transforms to a high-grade tumor over time. Example: Richter's transformation.
• Chemotherapy: treatment with drugs.
• Radiation therapy: treatment with radiations.
• Adjuvant therapy: treatment, either chemotherapy or radiation therapy, given after surgery to kill the remaining cancer cells.
• Prognosis: the probability of cure after the therapy. It is usually expressed as a probability of survival five years after diagnosis. Alternatively, it can be expressed as the number of years when 50% of the patients are still alive. Both numbers are derived from statistics accumulated with hundreds of similar patients to give a Kaplan-Meier curve.

Cancers are classified by the type of cell that resembles the tumor and, therefore, the tissue presumed to be the origin of the tumor. Examples of general categories include:

• Carcinoma: Malignant tumors derived from epithelial cells. This group represents the most common cancers, including the common forms of breast, prostate, lung and colon cancer.
• Sarcoma: Malignant tumors derived from connective tissue, or mesenchymal cells.
• Lymphoma and leukemia: Malignancies derived from hematopoietic (blood-forming) cells
• Germ cell tumor: Tumors derived from totipotent cells. In adults most often found in the testicle and ovary; in fetuses, babies, and young children most often found on the body midline, particularly at the tip of the tailbone; in horses most often found at the poll (base of the skull).
• Blastic tumor or blastoma: A tumor (usually malignant) which resembles an immature or embryonic tissue. Many of these tumors are most common in children.

Malignant tumors (cancers) are usually named using -carcinoma, -sarcoma or -blastoma as a suffix, with the Latin or Greek word for the organ of origin as the root. For instance, a cancer of the liver is called hepatocarcinoma; a cancer of the fat cells is called liposarcoma. For common cancers, the English organ name is used. For instance, the most common type of breast cancer is called ductal carcinoma of the breast or mammary ductal carcinoma. Here, the adjective ductal refers to the appearance of the cancer under the microscope, resembling normal breast ducts.

Benign tumors (which are not cancers) are named using -oma as a suffix with the organ name as the root. For instance, a benign tumor of the smooth muscle of the uterus is called leiomyoma (the common name of this frequent tumor is fibroid). Unfortunately, some cancers also use the -oma suffix, examples being melanoma and seminoma.

Child cancers

Cancer can also occur in young children and adolescents, but it is rare (about 150 cases per million yearly in the US). Statistics from the SEER program of the US NCI demonstrate that childhood cancers increased 19% between 1975 and 1990, mainly due to an increased incidence in acute leukemia. Since 1990, incidence rates have decreased.^[5]

There is a reasonable doubt that children living near nuclear facilities face an increased risk of cancer.^[6]

Infant cancers

The age of peak incidence of cancer in children occurs during the first year of life, in infants. The average annual incidence in the United States, 1975-1995, was 233 per million infants.^[5] Several estimates of incidence exist. According to SEER,^[5] in the United States:

• Neuroblastoma comprised 28% of infant cancer cases and was the most common malignancy among these young children (65 per million infants).
• The leukemias as a group (41 per million infants) represented the next most common type of cancer, comprising 17% of all cases.
• Central nervous system malignancies comprised 13% of infant cancer, with an average annual incidence rate of nearly 30 per million infants.
• The average annual incidence rates for malignant germ cell and malignant soft tissue tumors were essentially the same at 15 per million infants. Each comprised about 6% of infant cancer.

According to another study:^[4]

• Leukemia (usually ALL) is the most common infant malignancy (30%), followed by the central nervous system cancers and neuroblastoma. The remainder consists of Wilms' tumor, lymphomas, rhabdomyosarcoma (arising from muscle), retinoblastoma, osteosarcoma and Ewing's sarcoma.

Teratoma (a germ cell tumor) often is cited as the most common tumor in this age group, but most teratomas are surgically removed while still benign, hence not necessarily cancer. Prior to the widespread routine use of prenatal ultrasound examinations, the incidence of sacrococcygeal teratomas diagnosed at birth was 25 to 29 per million births.

Female and male infants have essentially the same overall cancer incidence rates, a notable difference compared to older children.

White infants have higher cancer rates than black infants. Leukemias accounted for a substantial proportion of this difference: the average annual rate for white infants (48.7 per million) was 66% higher than for black infants (29.4 per million).^[5]

Relative survival for infants is very good for neuroblastoma, Wilms' tumor and retinoblastoma, and fairly good (80%) for leukemia, but not for most other types of cancer.

Signs and symptoms

Roughly, cancer symptoms can be divided into three groups:

• Local symptoms: unusual lumps or swelling (tumor), hemorrhage (bleeding), pain and/or ulceration. Compression of surrounding tissues may cause symptoms such as jaundice (yellowing the eyes and skin).
• Symptoms of metastasis (spreading): enlarged lymph nodes, cough and hemoptysis, hepatomegaly (enlarged liver), bone pain, fracture of affected bones and neurological symptoms. Although advanced cancer may cause pain, it is often not the first symptom.
• Systemic symptoms: weight loss, poor appetite, fatigue and cachexia (wasting), excessive sweating (night sweats), anemia and specific paraneoplastic phenomena, i.e. specific conditions that are due to an active cancer, such as thrombosis or hormonal changes.

Every symptom in the above list can be caused by a variety of conditions (a list of which is referred to as the differential diagnosis). Cancer may be a common or uncommon cause of each item.

Diagnosis

Most cancers are initially recognized either because signs or symptoms appear or through screening. Neither of these lead to a definitive diagnosis, which usually requires the opinion of a pathologist, a type of physician (medical doctor) who specializes in the diagnosis of cancer and other diseases.

Investigation

People with suspected cancer are investigated with medical tests. These commonly include blood tests, X-rays, CT scans and endoscopy.

Biopsy

A cancer may be suspected for a variety of reasons, but the definitive diagnosis of most malignancies must be confirmed by histological examination of the cancerous cells by a pathologist. Tissue can be obtained from a biopsy or surgery. Many biopsies (such as those of the skin, breast or liver) can be done in a doctor's office. Biopsies of other organs are performed under anesthesia and require surgery in an operating room.

The tissue diagnosis given by the pathologist indicates the type of cell that is proliferating, its histological grade and other features of the tumor. Together, this information is useful to evaluate the prognosis of this patient and to choose the best treatment. Cytogenetics and immunohistochemistry are other types of testing that the pathologist may perform on the tissue specimen. These tests may provide information about future behavior of the cancer (prognosis) and best treatment.

Treatment

Cancer can be treated by surgery, chemotherapy, radiation therapy, immunotherapy, monoclonal antibody therapy or other methods. The choice of therapy depends upon the location and grade of the tumor and the stage of the disease, as well as the general state of the patient (performance status). A number of experimental cancer treatments are also under development.

Complete removal of the cancer without damage to the rest of the body is the goal of treatment. Sometimes this can be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.

Because "cancer" refers to a class of diseases, it is unlikely that there will ever be a single "cure for cancer" any more than there will be a single treatment for all infectious diseases.

Surgery

In theory, non-hematological cancers can be cured if entirely removed by surgery, but this is not always possible. When the cancer has metastasized to other sites in the body prior to surgery, complete surgical excision is usually impossible. In the Halstedian model of cancer progression, tumors grow locally, then spread to the lymph nodes, then to the rest of the body. This has given rise to the popularity of local-only treatments such as surgery for small cancers. Even small localized tumors are increasingly recognized as possessing metastatic potential.

Examples of surgical procedures for cancer include mastectomy for breast cancer and prostatectomy for prostate cancer. The goal of the surgery can be either the removal of only the tumor, or the entire organ. A single cancer cell is invisible to the naked eye but can regrow into a new tumor, a process called recurrence. For this reason, the pathologist will examine the surgical specimen to determine if a margin of healthy tissue is present, thus decreasing the chance that microscopic cancer cells are left in the patient.

In addition to removal of the primary tumor, surgery is often necessary for staging, e.g. determining the extent of the disease and whether it has metastasized to regional lymph nodes. Staging is a major determinant of prognosis and of the need for adjuvant therapy.

Occasionally, surgery is necessary to control symptoms, such as spinal cord compression or bowel obstruction. This is referred to as palliative treatment.

Radiation therapy

Main article: Radiation therapy

Radiation therapy (also called radiotherapy, X-ray therapy, or irradiation) is the use of ionizing radiation to kill cancer cells and shrink tumors. Radiation therapy can be administered externally via external beam radiotherapy (EBRT) or internally via brachytherapy. The effects of radiation therapy are localised and confined to the region being treated. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Hence, it is given in many fractions, allowing healthy tissue to recover between fractions.

Radiation therapy may be used to treat almost every type of solid tumor, including cancers of the brain, breast, cervix, larynx, lung, pancreas, prostate, skin, stomach, uterus, or soft tissue sarcomas. Radiation is also used to treat leukemia and lymphoma. Radiation dose to each site depends on a number of factors, including the radiosensitivity of each cancer type and whether there are tissues and organs nearby that may be damaged by radiation. Thus, as with every form of treatment, radiation therapy is not without its side effects.

Chemotherapy

Main article: Chemotherapy

Chemotherapy is the treatment of cancer with drugs ("anticancer drugs") that can destroy cancer cells. In current usage, the term "chemotherapy" usually refers to cytotoxic drugs which affect rapidly dividing cells in general, in contrast with targeted therapy (see below). Chemotherapy drugs interfere with cell division in various possible ways, e.g. with the duplication of DNA or the separation of newly formed chromosomes. Most forms of chemotherapy target all rapidly dividing cells and are not specific for cancer cells, although some degree of specificity may come from the inability of many cancer cells to repair DNA damage, while normal cells generally can. Hence, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate (e.g. intestinal lining). These cells usually repair themselves after chemotherapy.

Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called "combination chemotherapy"; most chemotherapy regimens are given in a combination.

The treatment of some leukaemias and lymphomas requires the use of high-dose chemotherapy, and total body irradiation (TBI). This treatment ablates the bone marrow, and hence the body's ability to recover and repopulate the blood. For this reason, bone marrow, or peripheral blood stem cell harvesting is carried out before the ablative part of the therapy, to enable "rescue" after the treatment has been given. This is known as autologous stem cell transplantation. Alternatively, hematopoietic stem cells may be transplanted from a matched unrelated donor (MUD).

Targeted therapies

Main article: Targeted therapy

Targeted therapy, which first became available in the late 1990s, has had a significant impact in the treatment of some types of cancer, and is currently a very active research area. This constitutes the use of agents specific for the deregulated proteins of cancer cells. Small molecule targeted therapy drugs are generally inhibitors of enzymatic domains on mutated, overexpressed, or otherwise critical proteins within the cancer cell. Prominent examples are the tyrosine kinase inhibitors imatinib and gefitinib.

Monoclonal antibody therapy is another strategy in which the therapeutic agent is an antibody which specifically binds to a protein on the surface of the cancer cells. Examples include the anti-HER2/neu antibody trastuzumab (Herceptin) used in breast cancer, and the anti-CD20 antibody rituximab, used in a variety of B-cell malignancies.

Targeted therapy can also involve small peptides as "homing devices" which can bind to cell surface receptors or affected extracellular matrix surrounding the tumor. Radionuclides which are attached to this peptides (e.g. RGDs) eventually kill the cancer cell if the nuclide decays in the vicinity of the cell. Especially oligo- or multimers of these binding motifs are of great interest, since this can lead to enhanced tumor specificity and avidity.

Photodynamic therapy (PDT) is a ternary treatment for cancer involving a photosensitizer, tissue oxygen, and light (often using lasers). PDT can be used as treatment for basal cell carcinoma (BCC) or lung cancer; PDT can also be useful in removing traces of malignant tissue after surgical removal of large tumors.^[7]

Immunotherapy

Main article: Cancer immunotherapy

Cancer immunotherapy refers to a diverse set of therapeutic strategies designed to induce the patient's own immune system to fight the tumor. Contemporary methods for generating an immune response against tumours include intravesical BCG immunotherapy for superficial bladder cancer, and use of interferons and other cytokines to induce an immune response in renal cell carcinoma and melanoma patients. Vaccines to generate specific immune responses are the subject of intensive research for a number of tumours, notably malignant melanoma and renal cell carcinoma. Sipuleucel-T is a vaccine-like strategy in late clinical trials for prostate cancer in which dendritic cells from the patient are loaded with prostatic acid phosphatase peptides to induce a specific immune response against prostate-derived cells.

Allogeneic hematopoietic stem cell transplantation ("bone marrow transplantation" from a genetically non-identical donor) can be considered a form of immunotherapy, since the donor's immune cells will often attack the tumor in a phenomenon known as graft-versus-tumor effect. For this reason, allogeneic HSCT leads to a higher cure rate than autologous transplantation for several cancer types, although the side effects are also more severe.

Hormonal therapy

Main article: Hormonal therapy (oncology)

The growth of some cancers can be inhibited by providing or blocking certain hormones. Common examples of hormone-sensitive tumors include certain types of breast and prostate cancers. Removing or blocking estrogen or testosterone is often an important additional treatment. In certain cancers, administration of hormone agonists, such as progestogens may be therapeutically beneficial.

Angiogenesis inhibitors

Main article: Angiogenesis inhibitor

Angiogenesis inhibitors prevent the extensive growth of blood vessels (angiogenesis) that tumors require to survive. Some, such as bevacizumab, have been approved and are in clinical use. One of the main problems with anti-angiogenesis drugs is that many factors stimulate blood vessel growth, in normal cells and cancer. Anti-angiogenesis drugs only target one factor, so the other factors continue to stimulate blood vessel growth. Other problems include route of administration, maintenance of stability and activity and targeting at the tumor vasculature.^[8]

Symptom control

Although the control of the symptoms of cancer is not typically thought of as a treatment directed at the cancer, it is an important determinant of the quality of life of cancer patients, and plays an important role in the decision whether the patient is able to undergo other treatments. Although doctors generally have the therapeutic skills to reduce pain, nausea, vomiting, diarrhea, hemorrhage and other common problems in cancer patients, the multidisciplinary specialty of palliative care has arisen specifically in response to the symptom control needs of this group of patients.

Pain medication, such as morphine and oxycodone, and antiemetics, drugs to suppress nausea and vomiting, are very commonly used in patients with cancer-related symptoms. Improved antiemetics such as ondansetron and analogues, as well as aprepitant have made aggressive treatments much more feasible in cancer patients.

Chronic pain due to cancer is almost always associated with continuing tissue damage due to the disease process or the treatment (i.e. surgery, radiation, chemotherapy). Although there is always a role for environmental factors and affective disturbances in the genesis of pain behaviors, these are not usually the predominant etiologic factors in patients with cancer pain. Furthermore, many patients with severe pain associated with cancer are nearing the end of their lives and palliative therapies are required. Issues such as social stigma of using opioids, work and functional status, and health care consumption are not likely to be important in the overall case management. Hence, the typical strategy for cancer pain management is to get the patient as comfortable as possible using opioids and other medications, surgery, and physical measures. Doctors have been reluctant to prescribe narcotics for pain in terminal cancer patients, for fear of contributing to addiction or suppressing respiratory function. The palliative care movement, a more recent offshoot of the hospice movement, has engendered more widespread support for preemptive pain treatment for cancer patients.

Fatigue is a very common problem for cancer patients, and has only recently become important enough for oncologists to suggest treatment, even though it plays a significant role in many patients' quality of life.

Treatment trials

Main article: Experimental cancer treatment

Clinical trials, also called research studies, test new treatments in people with cancer. The goal of this research is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy.

A clinical trial is one of the final stages of a long and careful cancer research process. The search for new treatments begins in the laboratory, where scientists first develop and test new ideas. If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects. Of course, treatments that work well in the lab or in animals do not always work well in people. Studies are done with cancer patients to find out whether promising treatments are safe and effective.

Patients who take part may be helped personally by the treatment they receive. They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer. At the same time, new treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit. There is no guarantee that a new treatment being tested or a standard treatment will produce good results. In children with cancer, a survey of trials found that those enrolled in trials were on average not more likely to do better or worse than those on standard treatment; this confirms that success or failure of an experimental treatment cannot be predicted.^[9]

Complementary and alternative

Main article: Unproven cancer therapy

Complementary and alternative medicine (CAM) treatments are the diverse group of medical and health care systems, practices, and products that are not part of conventional medicine.^[10] "Complementary medicine" refers to methods and substances used along with conventional medicine, while "alternative medicine" refers to compounds used instead of conventional medicine.^[11] CAM use is common among people with cancer; a 2000 study found that 69% cancer patients had used at least one CAM therapy as part of their cancer treatment.^[12] Most complementary and alternative medicines for cancer have not been rigorously studied or tested. Some alternative treatments which have been investigated and shown to be ineffective continue to be marketed and promoted.^[13]

Prognosis

Cancer has a reputation for being a deadly disease. While this certainly applies to certain particular types, the truths behind the historical connotations of cancer are increasingly being overturned by advances in medical care. Some types of cancer have a prognosis that is substantially better than nonmalignant diseases such as heart failure and stroke.

Progressive and disseminated malignant disease has a substantial impact on a cancer patient's quality of life, and many cancer treatments (such as chemotherapy) may have severe side-effects. In the advanced stages of cancer, many patients need extensive care, affecting family members and friends. Palliative care solutions may include permanent or "respite" hospice nursing.

Emotional impact

Many local organizations offer a variety of practical and support services to people with cancer. Support can take the form of support groups, counseling, advice, financial assistance, transportation to and from treatment, films or information about cancer. Neighborhood organizations, local health care providers, or area hospitals may have resources or services available.

Counseling can provide emotional support to cancer patients and help them better understand their illness. Different types of counseling include individual, group, family, peer counseling, bereavement, patient-to-patient, and sexuality.

Many governmental and charitable organizations have been established to help patients cope with cancer. These organizations often are involved in cancer prevention, cancer treatment, and cancer research.