Skin cancer is the most common type of cancer. Skin cancer is diagnosed in more than one million people a year. Cancer occurs when cells grow abnormally and multiply.

As the cells multiply they form a tumor. Tumors may travel to distant organs through the blood stream or lymphatic tissues. This spread is called metastasis. Tumors overtake normal tissue by invading its space and taking the oxygen and nutrients it needs to survive.

There are three kinds of skin cancer: basal cell cancer, squamous cell cancer and melanoma. The majority of skin cancers are basal cell or squamous cell cancer. These are unlikely to spread to other tissues. A small amount of skin cancers are melanoma. These are very aggressive and can be fatal and do spread to other parts of the body.

Skin cancers start as precancerous lesions. These lesions can turn into cancer if left untreated. Actinic keratosis is precancerous. These lesions are patches of red or brown, scaly, rough skin which can turn into squamous cell cancer. A mole that changes can turn into melanoma over time. Most people have 10 to 40 moles. Very few moles become cancer. When you develop a hundred or more moles this does increase your risk of skin cancer. Also when moles become irregularly shaped, larger than ¼ inch in diameter and are mixed in color this increases risk of cancer.

Sunlight is the most common cause of skin cancer. Tanning beds expose you to even more concentrated UV radiation than sun exposure, which is more dangerous than being out in the sun. Exposure to high levels of x-ray, and contact with certain arsenic chemicals can also increase your risk of skin cancer.

People at highest risk are those with a combination of fair skin, blonde or red hair, and blue or green eyes. People with family members with skin cancer are also at risk. People with at least one severe sun burn in their lifetime are at risk as well.

Basal cell and squamous cell cancer are more common in older patients. Melanoma is more common in younger people, usually between age 25 and 29. Basal cell cancer looks like a raised, smooth bump on the skin of the head, neck or shoulders. An area of crusting or bleeding may be found in the center of the bump. Basal cells are usually mistaken for sores that don’t heal. Squamous cell cancer is red, scaly, thickened patches of skin. They may ulcerate or bleed. Melanomas are brown or black moles. They change in size, color or texture.

If you develop a new mole in adulthood, or have itching, ulcer, or bleeding of an existing mole it should be checked out by a physician. Warning signs of melanoma are the ABCD’s of skin. Asymmetry is when one side of the lesion doesn’t look like the other. Border irregularity is when margins are irregular. Color changes or mixtures of brown, black, red or white. Diameter is when lesions are larger than a pencil eraser across.

People at highest risk should check themselves frequently. Any unusual lesions or changing mole should be checked by a physician. Any worrisome mole or lesion may be biopsied or removed. In basal cell and squamous cell removal of the lesion is usually all that is needed. Melanoma treatment usually requires surgery, radiation and chemotherapy. Prevention is always the best medicine. Frequent self-exams, avoiding sun exposure, and wearing sunscreen all reduce risk of skin cancer.