Here Comes the Sun and The Threat of Skin Cancer

Each year, there are an estimated 1 million new cases of skin cancer. It is the most common form of human cancer, and its annual rates are increasing on a yearly basis. The main cause of most skin cancer is ultraviolet (UV) light. There are three different conditions that are commonly referred to as "skin cancer" - basal cell carcinoma, squamous cell carcinoma, and melanoma.

Basal cell carcinoma (also basal cell carcinoma epithelioma) is the most common, accounting for over 90% of U.S. skin cancer diagnoses. It almost never spreads to other parts of the body, but can cause damage to surrounding tissues. Two of the most important factors in its development are skin coloring and age: Older people with light-colored skin have higher rates. Other risk factors include weakened immune system, sun exposure (UV radiation), therapeutic radiation used in treatment for other cancers, and exposure to UV radiation through tanning booths.

It begins as a dome-shaped bump; its appearance can be referred to as shiny or translucent, and can often be mistaken for a flesh-colored mole. Doctors will usually remove all or part of this growth to perform a biopsy. There are many treatment methods, most of which have a success rate around 90%; these include surgery, radiation therapy, cryosurgery, and medical therapy using creams.

Squamous cell carcinoma begins in the squamous cells, which are found in the tissues that form skin, hollow organ linings, and respiratory and digestive tract passages. Light-colored skin and sun exposure are again among important factors in development, and women tend to be less affected than men. Less common factors include exposure to arsenic, hydrocarbons, heat, or x-rays; and a weakened immune system. This type can spread to other parts of the body.

The earliest form is referred to as actinic (solar) keratosis, which appears as rough, red bumps and is often sore and tender. Diagnosis is made most often via punch biopsy; treatment techniques are very similar to those for basal cell carcinoma.

Melanoma occurs in the melanocytes (pigment cells). Not only can it occur in the skin (cutaneous melanoma), but also in the eye (ocular or intraocular melanoma). It is rare in people of dark skin coloring. It can occur on all skin surfaces, and can spread, with cancer cells sometimes showing up in lymph nodes near its origin.

There are no exact causes of melanoma, but there are a number of risk factors that may increase the chances for development - having over 50 moles on one's body, fair skin coloring, personal and family history of melanoma, a weakened immune system, blistering sunburns (especially as a child), and natural- and artificial-source exposure to UV radiation.

Melanoma is most often characterized by a change in appearance (size, shape, color, feel) of an existing mole. A biopsy is performed by removing some or all of the growth (preferably all); if confirmed, melanoma is then "staged" (the extent to which the disease has progressed). Methods of treatment include surgery, chemotherapy, biological therapy, radiation therapy, or a combination of these treatments, dependent on stage.

If you have any questions or concerns about your skin or a particular patch or growth, please see your doctor, as only he or she can take the proper steps to assure a complete and proper diagnosis.

Sources: Alan Rockoff, MD, "Skin Cancer (Nonmelanoma Skin Cancer)," Medicinenet
"Melanoma," Medicinenet