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Skin cancer

Skin cancer
It is estimated that approximately 85% of cases are caused by too much sun. Nonmelanoma skin cancers are the most common 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.

Risk factors
A basal cell carcinoma, one of the most common types of skin cancer.
Skin cancer Classification and external resources ICD-10 ICD-9 ICD-O: MeSH C43.-C44. 172, 173 8010-8720 D012878

Skin cancer is a malignant growth on the skin which can have many causes. The most common skin cancers are basal cell cancer, squamous cell cancer, and melanoma. 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. 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.[1] Skin cancer represents the most commonly diagnosed cancer, surpassing lung, breast, colorectal and prostate cancer.[1] Melanoma is less common than basal cell carcinoma and squamous cell carcinoma, but it is the most serious -- for example, in the UK there are 9,500 new cases of melanoma each year, and 2,300 deaths.[2] More people now die of Melanoma in the UK than in Australia. It is the most common cancer in the young population (20 – 39 age group).[3]

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. Since sunbeds cause mostly indirect DNA damage (free radicals) their use is associated with the deadliest form of skin cancer, malignant melanoma. 1. 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. 2. 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. 2. Chronic non-healing wounds, especially burns. These are called Marjolin’s ulcers based on their appearance, and can develop into squamous cell carcinoma.

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3. 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. 4. Human papilloma virus (HPV) is often associated with squamous cell carcinoma of the genital, anal, oral, pharynx, and fingers. It is believed that the HPV vaccine might help to prevent these cancers as well as cervical cancers. 5. Skin cancer is one of the potential dangers of ultraviolet germicidal irradiation. Many believe that skin cancer can be prevented altogether by avoiding sunlight entirely, or wearing protective clothing while outdoors. However, studies show that Melanoma Skin Cancer is more common in those who work indoors. Skin Cancer is most common on areas of the body that are not normally exposed to the sun, and then exposing the skin to UV rays excessively. Skin cancer generally has a 20- to 30-year latency period. Many instances of skin cancer in older individuals today can be traced to behaviours as young adults in the 1970s and early 1980s. Deep tans at that time were routinely spoken of as "healthy." Sunburns represented an inconvenient rite of spring or an awkward preliminary stage in the process of acquiring a "healthy" tan. Severe burns were commonplace. Today we know the approach to be reckless. The incidence rates of skin cancer today in persons over 50 years of age reflect that day’s popular ignorance.

Skin cancer
the 3 common skin cancers. They frequently metastasize, and are deadly once spread. Less common skin cancers include: Dermatofibrosarcoma protuberans, Merkel cell carcinoma, Kaposi’s sarcoma, keratoacanthoma, spindle cell tumors, sebaceous carcinomas, microcystic adnexal carcinoma, Pagets’s disease of the breast, atypical fibroxanthoma, leimyosarcoma, and angiosarcoma The BCC and the SCC often carry a UVsignature 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. The indirect DNA damage is caused by free radicals and reactive oxygen species. Research indicates 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. [4]

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 6500 deaths per year.[5]:29,31 Even though it is much less common than BCCs and SCCs, malignant melanoma is responsible for 75% of all skin cancer-related deaths.[6] 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[4]. It has been found that sunscreen use is correlated with malignant melanoma. [7][8][9][10][11][12] The lab-experiments and the epidemiological studies suggests that sunscreen use correlates with melanoma incidence. The question that has

Types
The most common types of skin cancers are: • • • Basal cell carcinomas (BCC) are the most common. They are present on sun-exposed areas of the skin, especially the face. They rarely metastasize, and rarely cause death. They are easily treated with surgery or radiation. Squamous cell carcinomas(SCC) are common, but much less common than basal cell cancers. They metastasize more frequently than BCCs. Even then, the metastasis rate is quite low, with the exception of SCCs of the lip, ear, and in immunosuppressed patients. Melanomas are the least frequent of

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to be asked is: "Are sunscreen users also the ones with the highest lifetime exposure to ultraviolet lights?" or are sun screens tumor promoters or carcinogens themselves. Logics might suggest that sunscreen users also are the ones most likely to be burned or have been burned by sun light. If it is true that some suncreen induces the formation of skin cancers, the physical sunscreen which are metallic in nature (zinc and titanium) are likely safer and likely to be inert. In the past, most sunscreens were chemical blockers (benzones, etc.).

Skin cancer

Signs and symptoms
There are a variety of different skin cancer symptoms. These include changes in the skin that do not heal, ulcering in the skin, discolored skin, and changes in existing moles. Such as jagged edges to the mole, and enlargement of the mole • Basal cell carcinoma usually looks like a raised, smooth, pearly bump on the sunexposed skin of the head, neck or shoulders. Sometimes small blood vessels can be seen within the tumor. Crusting and bleeding in the center of the tumor frequently develops. It is often mistaken for a sore that does not heal. This form of skin cancer is the least deadly and with proper treatment can be completely eliminated with not so much as a single scar • Squamous cell carcinoma is commonly a red, scaling, thickened patch on sunexposed skin. Ulceration and bleeding may occur. When SCC is not treated, it may develop into a large mass. Squamous cell is the second most common skin cancer, it is dangerous, but not nearly as dangerous as Melanoma • Most melanomas are brown to black looking lesions. Signs that might indicate a malignant melanoma include change in size, shape, color or elevation of a mole. Other signs are the appearance of a new mole during adulthood or new pain, itching, ulceration or bleeding.

A dermatoscope.

A modern polarized dermatoscope. diagnosis can only be confirmed with a skin biopsy. Most skin biopsies are done under local anesthetic with an injection. A shave biopsy is good for diagnosing basal cell carcinoma, while not as well for squamous cell carcinoma. A punch biopsy is preferred for diagnosing squamous cell carcinoma and melanoma over the shave biopsy technique. Excisional biopsy (where the entire lesion is removed down to the deep dermis and subcutanous fat) is the method of choice for diagnosing melanomas. However, for cosmetic reason and practical reasons, a punch biopsy is often used to initially diagnose many large melanomas or melanomas of cosmetically important anatomic locations (nose, face, eyelids, nails, fingers and toes).

Diagnosis
Clinical diagnosis is made with visual appearance or with the aid of a dermatoscope. The ABCD guideline is helpful for identifying dysplastic nevus and melanoma. Clinical

Treatment
Treatment is dependent on type of cancer, location of the cancer, age of the patient, and if the cancer is primary or recurrence. One should look at the specific type of skin cancer

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(basal cell carcinoma, squamous cell carcinoma, or melanoma) of concern in order to determine the correct treatment required. An example would be a small basal cell cancer on the cheek of a young man, where the treatment with the best cure rate (Mohs surgery) might be indicated. In the case of an elderly frail man with multiple complicating medical problems, a difficult to excise basal cell cancer of the nose might warrant radiation therapy (slightly lower cure rate) or no treatment at all. Topical chemotherapy might be indicated for large superficial basal cell carcinoma for good cosmetic outcome, whereas it might be inadequate for invasive nodular basal cell carcinoma or invasive squamous cell carcinoma. For low-risk disease, radiation therapy, topical chemotherapy (imiquimod or 5-fluorouracil) and cryotherapy (freezing the cancer off) can provide adequate control of the disease; both, however, may have lower overall cure rates than certain type of surgery. Other modalities of treatment such as photodynamic therapy, topical chemotherapy, electrodessication and curettage can be found in the discussions of basal cell carcinoma and squamous cell carcinoma. Mohs’ micrographic surgery (mohs 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.[13] 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

Skin cancer
chemotherapy. This type of treatment if shown to be effective has no side effects and could change the way cancer patients are treated. [14]

Reconstruction after removal of skin cancers
Currently, surgical excision is the most common form of treatment for skin cancers. The goal of reconstructive surgery is restoration of normal appearance and function. The choice of technique in reconstruction is dictated by the size and location of the defect. Excision and reconstruction of facial skin cancers is generally more challenging due to presence of highly visible and functional anatomic structures in the face. When skin defects are small in size, most can be repaired via simple repair whereby skin edges are approximated and closed with sutures. This will result in a linear scar. If the repair is made along a natural skin fold or wrinkle line, the scar will be hardly visible. Larger defects may require repair with a skin graft, local skin flap, pedicled skin flap, or a microvascular free flap. Skin grafts and local skin flaps are by far more common than the other listed choices. Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster is placed atop the graft for seven to ten days, to immobilize the graft as it heals in place. There are two forms of skin grafting: split thickness and full thickness. In a split thickness skin graft, a shaver is used to shave a layer of skin from the abdomen or thigh. The donor site, regenerates skin and heals over a period of two weeks. In a full thickness skin graft, a segment of skin is totally removed and the donor site needs to be sutured closed. [15] Split thickness grafts can be used to repair larger defects, but the grafts are inferior in their cosmetic appearance. Full thickness skin grafts are more acceptable cosmetically. However, full thickness grafts can only be used for small or moderate sized defects. Local skin flaps are a method of closing defects with tissue that closely matches the defect in color and quality. Skin from the periphery of the defect site is mobilized and repositioned to fill the deficit. Various forms of local flaps can be designed to minimize

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disruption to surrounding tissues and maximize cosmetic outcome of the reconstruction. Pedicled skin flaps are a method of transferring skin with an intact blood supply from a nearby region of the body. An example of such reconstruction is a pedicled forehead flap for repair of a large nasal skin defect. Once the flap develops a source of blood supply form its new bed, the vascular pedicle can be detached. Source*[2]

Skin cancer
subjacent connective tissue (dermis). In well differentiated carcinomas, tumor cells are pleomorphic/atypical, but resembling normal keratinocytes from prickle layer (large, polygonal, with abundant eosinophilic (pink) cytoplasm and central nucleus). Their disposal tends to be similar to that of normal epidermis: immature/basal cells at the periphery, becoming more mature to the centre of the tumor masses. Tumor cells transform into keratinized squamous cells and form round nodules with concentric, laminated layers, called "cell nests" or "epithelial/keratinous pearls". The surrounding stroma is reduced and contains inflammatory infiltrate (lymphocytes). Poorly differentiated squamous carcinomas contain more pleomorphic cells and no keratinization.[17]

Reduction of risk
Although it is impossible to completely eliminate the possibility of skin cancer, the risk of developing such a cancer can be reduced significantly with the following steps: • reducing exposure to ultraviolet (UV) radiation, especially in early years • avoiding sun exposure during the day, especially from 9 AM to 4 PM when the sun is highest in the sky • wearing protective clothing (long sleeves and hats) when outdoors • using a broad-spectrum sunscreen that blocks both UVA and UVB radiation • reapply sun block every 2 hours and after swimming • chemoprevention using topical imiquimod or 5-fluorouracil Although it is generally accepted that UV exposure is the greatest risk factor in melanoma development, some sceptics say no data conclusively proves a link between moderate sun exposure and the likelihood of melanoma. Australian scientist Ian Frazer who developed a vaccine for cervical cancer, says that a vaccine effective in preventing for certain types of skin cancer has proven effective on animals and could be available within a decade. The vaccine would only be effective against Squamous Cell Carcinoma.[16]

See also
• • • • • Mohs surgery Skin biopsy Sun protective clothing Sunscreen controversy Captain Cutaneum

References
[1] ^ National Cancer Institute - Common Cancer Types (http://www.cancer.gov/ cancertopics/commoncancers) [2] http://news.bbc.co.uk/2/hi/health/ 7985323.stm [3] http://www.mirror.co.uk/news/topstories/2009/04/08/skin-cancer-killingsunbed-generation-115875-21262348/ [4] ^ Hanson Kerry M.; Gratton Enrico; Bardeen Christopher J. (2006), "Sunscreen enhancement of UV-induced reactive oxygen species in the skin", Free Radical Biology and Medicine 41 (8): 1205–1212, doi:10.1016/ j.freeradbiomed.2006.06.011. [5] C. C. Boring, T. S. Squires and T. Tong (1991), "Cancer statistics, 1991", SA Cancer Journal for Clinician 41: 19–36, doi:10.3322/canjclin.41.1.19, http://caonline.amcancersoc.org/cgi/ reprint/41/1/19.pdf. [6] "Early Detection and Treatment of Skin Cancer", American Family Physician, July 2000, http://www.aafp.org/afp/20000715/ 357.html, retrieved on 2008-04-21. [7] Garland C, Garland F, Gorham E (1992), "Could sunscreens increase melanoma

Pathology
Squamous cell carcinoma is a malignant epithelial tumor which originates in epidermis, squamous mucosa or areas of squamous metaplasia. Macroscopically, the tumor is often elevated, fungating, or may be ulcerated with irregular borders. Microscopically, tumor cells destroy the basement membrane and form sheets or compact masses which invade the

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From Wikipedia, the free encyclopedia
risk?", Am J Public Health 82 (4): 614–5, doi:10.2105/AJPH.82.4.614, PMID 1546792, http://www.ajph.org/cgi/ reprint/82/4/614. [8] Westerdahl J; Ingvar C; Masback A; Olsson H (2000), "Sunscreen use and malignant melanoma.", International journal of cancer. Journal international du cancer 87: 145–50, doi:10.1002/ 1097-0215(20000701)87:1<145::AIDIJC22>3.0.CO;2-3. [9] Autier P; Dore J F; Schifflers E; et al. (1995), "Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France", Int. J. Cancer 61: 749–755, doi:10.1002/ ijc.2910610602. [10] Weinstock, M. A. (1999), "Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation.", Journal of Investigative Dermatology Symposium Proceedings 4: 97–100, doi:10.1038/ sj.jidsp.. [11] Vainio, H., Bianchini, F. (2000), "Cancerpreventive effects of sunscreens are uncertain.", Scandinavian Journal of Work Environment and Health 26: 529–31. [12] Ainsleigh HG (1993), "Beneficial effects of sun exposure on cancer mortality.", Prev Med. 22 (1): 132–40, doi:10.1006/ pmed.1993.1010, PMID 8475009.

Skin cancer
[13] Doherty, Gerard M.; Mulholland, Michael W. (2005). Greenfield’s Surgery: Scientific Principles And Practice. Baltimore: Williams & Wilkins. ISBN 0-7817-5626-X. [14] [1] [15] Maurice M Khosh, MD, FACS, "Skin Grafts, Full-Thickness", eMedicine, http://emedicine.medscape.com/article/ 876379-overview. [16] Cosmos Online - Skin cancer vaccine within reach (http://www.cosmosmagazine.com/news/ 2327/skin-cancer-vaccine-within-reach) [17] ""Squamous cell carcinoma (epidermoid carcinoma) - skin" pathologyatlas.ro", http://www.pathologyatlas.ro/squamouscell-carcinoma-skin.php, retrieved on 2007-07-21.

External links
• Medical Encyclopedia WebMD: Melanoma/Skin Cancer Health Center • Medical Encyclopedia WebMD: Skin Cancer, Non Melanoma Guide • Medical Encyclopedia MayoClinic: Skin cancer • Interactive Health Tutorials Medline Plus: Skin cancer Using animated graphics and you can also listen to the tutorial • Skin cancer at the Open Directory Project • Skin cancer at the Yahoo! Directory

Retrieved from "http://en.wikipedia.org/wiki/Skin_cancer" Categories: Types of cancer This page was last modified on 22 May 2009, at 22:26 (UTC). All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) taxdeductible nonprofit charity. Privacy policy About Wikipedia Disclaimers

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