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 which all trace back to the mutilation of melanin cells. 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 and likely 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] It is estimated that approximately 85% of cases are caused by too much sun.[citation needed] Non-melanoma 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
Skin cancer is most closely associated with chronic inflammation of the skin. This includes:
Overexposure to UV-radiation can cause skin cancer either via the direct DNA damage or v
ia 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.[citation needed] 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. 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. 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. 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. 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[citation needed]. Many instances of skin cancer in older individuals today can be traced to behaviours as young adults in the 1970s and early 1980s[citation needed]. 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[citation needed].
Overexposure to UV-radiation can cause skin cancer either via the direct DNA damage or v
ia 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.[citation needed] 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. 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. 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. 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. 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[citation needed]. Many instances of skin cancer in older individuals today can be traced to behaviours as young adults in the 1970s and early 1980s[citation needed]. 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[citation needed].
Types
The most common types of skin cancers are:
Basal Cell Carcinoma Squamous Cell Carcinoma Melanoma Basal cell carcinomas (BCC) is 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 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 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. 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, if applied in too little quantities and too infrequently. [4] However, the researchers add that newer creams often do not contain these specific compounds, and that the combination of other ingredients tends to retain the compounds on the surface of the skin. They also add the frequent re-application reduces the risk of radical formation.
Basal Cell Carcinoma Squamous Cell Carcinoma Melanoma Basal cell carcinomas (BCC) is 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 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 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. 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, if applied in too little quantities and too infrequently. [4] However, the researchers add that newer creams often do not contain these specific compounds, and that the combination of other ingredients tends to retain the compounds on the surface of the skin. They also add the frequent re-application reduces the risk of radical formation.
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 sun-exposed 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 sun-exposed 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 a 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. Merkel cell carcinomas are most often rapidly growing, non-tender red, purple or skin colored bumps that are not painful or itchy. They may be mistaken for a cyst or other type of cancer.[13]
Basal cell carcinoma usually looks like a raised, smooth, pearly bump on the sun-exposed 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 sun-exposed 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 a 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. Merkel cell carcinomas are most often rapidly growing, non-tender red, purple or skin colored bumps that are not painful or itchy. They may be mistaken for a cyst or other type of cancer.[13]
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 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).
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).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 (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.[14]
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. [15]
A cream used to treat pre-cancerous skin lesions also reverses signs of ageing, a study released in April 2009 indicated.[16]
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.[14]
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. [15]
A cream used to treat pre-cancerous skin lesions also reverses signs of ageing, a study released in April 2009 indicated.[16]
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[citation needed] 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.
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[citation needed] 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.
