Skin Cancer

basal cell carcinoma removal scar
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Definition:
Skin cancer is the uncontrolled growth of abnormal skin cells. If left unchecked, these cancer cells can spread from the skin into other tissues and organs.It is a malignant growth on the skin which can have many causes. Skin cancer generally develops in the epidermis (the outermost layer of skin), so a tumor is usually clearly visible. This makes most skin cancers detectable in the early stages. There are three common types of skin cancer, each of which is named after the type of skin cell from which it arises. Cancers caused by UV exposure may be prevented by avoiding exposure to sunlight or other UV sources, and wearing sun-protective clothes. The use of sunscreen is recommended by medical organizations as a measure that helps to protect against skin cancer (see sunscreen).

Unlike many other cancers, including those originating in the lung, pancreas, and stomach, only a small minority of those afflicted will actually die of the disease.[citation needed] Skin cancers are the fastest growing type of cancer in the United States. Skin cancer represents the most commonly diagnosed malignancy, surpassing lung, breast, colorectal and prostate cancer. Melanoma is the least common skin cancer but it is potentially the most serious: there are over 8,000 new cases each year in the UK and 1,800 deaths. More people now die of Melanoma in the UK than in Australia. It is the second most common cancer in the young population (20 – 39 age group). It is estimated that approximately 85% of cases are caused by too much sun. Non-melanoma skin cancers are the commonest skin cancers. The majority of these are called Basal Cell Carcinomas. These are usually localised growths caused by excessive cumulative exposure to the sun and do not tend to spread.

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Types:-
There are different types of skin cancer. Basal cell carcinoma is the most common. Melanoma is less common, but more dangerous.

More rare types of skin cancer include:
*Dermatofibrosarcoma protuberans
*Merkel cell carcinoma
*Kaposi’s sarcoma

The BCC and the SCC often carry a UV-signature mutation indicating that these cancers are caused by UV-B radiation via the direct DNA damage. However the malignant melanoma is predominantly caused by UV-A radiation via the indirect DNA damage.[citation needed] The indirect DNA damage is caused by free radicals and reactive oxygen species. It has been shown, that the absorption of three sunscreen ingredients into the skin, combined with a 60-minute exposure to UV, leads to an increase of free radicals in the skin.

Skin cancer as a group:-
Many laymen and even professionals consider the basal cell carcinoma (BCC), the squamous cell carcinoma (SCC) and the malignant melanoma as one group – namely skin cancer. This grouping is problematic for two reasons:

*the mechanism that generates the first two forms is different from the mechanism that generates the melanoma. The direct DNA damage is responsible for BCC and SCC while the indirect DNA damage causes melanoma.

*the mortality rate of BCC and SCC is around 0.3 causing 2000 deaths per year in the US. In comparison the mortality rate of melanoma is 15-20% and it causes 138001 deaths per year.

Even though it is rare, malignant melanoma is responsible for 75 % of all skin cancer related death cases.

While sunscreen has been shown to protect against BCC and SCC it may not protect against malignant melanoma. When sunscreen penetrates into the skin it generates reactive chemicals. It has been found that sunscreen use is correlated with malignant melanoma. The lab-experiments and the epidemiological studies indicate that sunscreen use causes melanoma.

Causes:
The outer layer of skin, the epidermis, is made up of different types of cells. Skin cancers are classified by the types of epidermal cells involved:

Basal cell carcinoma develops from abnormal growth of the cells in the lowest layer of the epidermis and is the most common type of skin cancer.
Squamous cell carcinoma involves changes in the squamous cells, found in the middle layer of the epidermis.
Melanoma occurs in the melanocytes (cells that produce pigment) and is less common than squamous or basal cell carcinoma, but more dangerous. It is the leading cause of death from skin disease.
Skin cancers are sometimes classified as either melanoma or nonmelanoma. Basal cell carcinoma and squamous cell carcinoma are the most common nonmelanoma skin cancers. Other nonmelanoma skin cancers are Kaposi’s sarcoma, Merkel cell carcinoma, and cutaneous lymphoma.

Skin cancer is the most common form of cancer in the Unites States. Known risk factors for skin cancer include the following:

*Complexion: Skin cancers are more common in people with light-colored skin, hair, and eyes.
*Genetics: Having a family history of melanoma increases the risk of developing this cancer.
*Age: Nonmelanoma skin cancers are more common after age 40.
*Sun exposure and sunburn: Most skin cancers occur on areas of the skin that are regularly exposed to sunlight or other

*ultraviolet radiation. This is considered the primary cause of all skin cancers.

Skin cancer can develop in anyone, not only people with these risk factors. Young, healthy people — even those with with dark skin, hair, and eyes — can develop skin cancer.

Symptoms:
Skin cancers may have many different appearances. They can be small, shiny, waxy, scaly and rough, firm and red, crusty or bleeding, or have other features. Therefore, anything suspicious should be looked at by a physician. See the articles on specific skin cancers for more information.

Here are some features to look for:

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*Asymmetry: one half of the abnormal skin area is different than the other half
*Borders: irregular borders
*Color: varies from one area to another with shades of tan, brown, or black (sometimes white, red, blue)
*Diameter: usually (but not always) larger than 6 mm in size (diameter of a pencil eraser)

Any skin growth that bleeds or will not heal
Use a mirror or have someone help you look on your back, shoulders, and other hard-to-see areas.

Risk factors:-
Skin cancer is most closely associated with chronic inflammation of the skin. This includes:

1.Overexposure to UV-radiation can cause skin cancer either via the direct DNA damage or via the indirect DNA damage mechanism. UVA & UVB have both been implicated in causing DNA damage resulting in cancer. Sun exposure between 10AM and 4PM is most intense and therefore most harmful. Natural (sun) & artificial UV exposure (tanning salons) are associated with skin cancer.[citation needed] Since sunbeds cause mostly indirect DNA damage (free radicals) their use is associated with the deadliest form of skin cancer, malignant melanoma.

2.UVA rays affect the skin at a deeper level than UVB rays, reaching through the epidermis and the dermis to the hypodermis where connective tissues and blood vessels are located. UVA activates the melanin of the epidermis causing changes in pigmentation as well as loss of elasticity of the skin, which contributes to premature wrinkling, sagging and aging of the skin.

3.UVB rays primarily affect the epidermis causing sunburns, redness, and blistering of the skin. The melanin of the epidermis is activated with UVB just as with UVA; however, the effects are longer lasting with pigmentation continuing over 24 hours.
Chronic non-healing wounds, especially burns. These are called Marjolin’s ulcers based on their appearance, and can develop into squamous cell carcinoma.

4.Genetic predisposition, including “Congenital Melanocytic Nevi Syndrome”. CMNS is characterized by the presence of “nevi” or moles of varying size that either appear at or within 6 months of birth. Nevi larger than 20 mm (3/4″) in size are at higher risk for becoming cancerous.

5.Skin cancer is one of the potential dangers of ultraviolet germicidal irradiation.
Skin can be protected by avoiding sunlight entirely, or wearing protective clothing while outdoors. Skin cancer is usually caused by exposing skin to UV rays excessively.

Treatment:-
Most skin cancers can be treated by removal of the lesion, making sure that the edges (margins) are free of the tumor cells. These excisions provide the best cure for both early and high-risk disease.

For low-risk disease, radiation therapy and cryotherapy (freezing the cancer off) can provide adequate control of the disease; both, however, have lower overall cure rates than surgery.

Mohs’ micrographic surgery is a technique used to remove the cancer with the least amount of surrounding tissue and the edges are checked immediately to see if tumor is found. This provides the opportunity to remove the least amount of tissue and provide the best cosmetically favorable results. This is especially important for areas where excess skin is limited, such as the face. Cure rates are equivalent to wide excision. Special training is required to perform this technique.

In the case of disease that has spread (metastasized), further surgical procedures or chemotherapy may be required.

Scientists have recently been conducting experiments on what they have termed “immune- priming”. This therapy is still in its infancy but has been shown to effectively attack foreign threats like viruses and also latch onto and attack skin cancers. More recently researchers have focused their efforts on strengthening the body’s own naturally produced “helper T cells” that identify and lock onto cancer cells and help guide the killer cells to the cancer. Researchers infused patients with roughly 5 billion of the helper T cells without any harsh drugs or chemotherapy. This type of treatment if shown to be effective has no side effects and could change the way cancer patients are treated.

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Prognosis:-
The outlook depends on a number of factors, including the type of cancer and how quickly it was diagnosed. Basal cell carcinoma and squamous cell carcinoma rarely spread to other parts of the body. However, melanoma is more likely to spread. See the specific skin cancer articles for additional information.

Prevention :-
Minimizing sun exposure is the best way to prevent skin damage, including many types of skin cancer:

*Protect your skin from the sun when you can — wear protective clothing such as hats, long-sleeved shirts, long skirts, or pants.
*Try to avoid exposure during midday, when the sun is most intense.
*Use sunscreen with an SPF of at least 15. Apply sunscreen at least one-half hour before sun exposure, and reapply frequently.
*Apply sunscreen during winter months as well.
*Reapply sun block every 2 hours and after swimming

Although it is generally accepted that UV exposure is the greatest risk factor in melanoma development, some sceptics say that there is no proven data that links moderate sun exposure with the appearance of melanoma.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.nlm.nih.gov/medlineplus/ency/article/001442.htm
http://en.wikipedia.org/wiki/Skin_cancer

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