Skin cancer is a malignant growth on the skin which can have many causes. Skin cancer is the most common form of human cancer. Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. Basal cell carcinoma (BCC) is the most common form of cancer, with about a million new cases estimated in the U.S. each year. Basal cells line the deepest layer of the epidermis. Basal cell carcinomas are malignant growths--tumors--that arise in this layer. Cancers caused by UV exposure may be prevented by avoiding exposure to sunlight or other UV sources, wearing sun-protective clothes, and using a broad-spectrum sun screen. Skin cancers are the fastest growing type of cancer in the United States.

The sun is responsible for over 90 percent of all skin cancers. The most common sign of skin cancer is a change on the skin, such as a growth or a sore that won't heal. Sometime there may be a small lump. Melanoma is the most serious form of skin cancer. It affects deeper layers of the skin and has the greatest potential to spread to other tissues in the body. It is one of the rarer types of skin cancer but causes the majority of skin cancer related deaths. It is more common in caucasian populations living in sunny climates than other groups. Melanoma can also appear on the body as a new mole. Men most often get melanoma on the trunk (the area of the body between the shoulders and hips) or on the head or neck; women most often get melanoma on the arms and legs.

Squamous cell carcinoma is a form of cancer of the carcinoma. This type of cancer is characterized by red, scaly skin that becomes an open sore. Light-colored skin and a history of sun exposure are even more important in predisposing to this kind of cancer than to basal cell carcinoma. Squamous cell carcinoma affects more than 200,000 people in the United States alone every year. Smoking is a significant risk factor. Squamous cell carcinoma of the skin is often caused by long term exposure to the sun. Other risk factors include sun exposure, radiation therapy, exposure to carcinogens, chronic skin irritation or inflammation, genetic diseases, and presence of premalignant lesions. Squamous cell carcinoma is usually developed in the epithelial layer of the skin.

Treatment for skin cancer and the precancerous skin lesions known as actinic keratoses varies, depending on the size, type, depth and location of the lesions. Radiation therapy and cryotherapy can provide adequate control of the disease; both, however, have lower overall cure rates than surgery. Alternative medicine approaches that endeavor to optimize the capabilities of the immune system against cancer are especially attractive. Avoiding sun exposure in susceptible individuals is the best way to lower the risk for all types of skin cancer. Regular surveillance of susceptible individuals, both by self-examination and regular physical examination, is also a good idea for people at higher risk. People who have already had any form of skin cancer should have regular medical checkups.