Medical Edge Newspaper Column

Treating and Preventing Skin Cancer

April 29, 2007
Dear Mayo Clinic:
Is excision the only treatment for skin cancer? Are there any preventive measures that one can take aside from staying out of the sun? -- Enid, Okla.

Answer:
There are other treatment options for skin cancer. And surgical removal can be accomplished several different ways. The patient and doctor determine the best treatment, taking into account the size, type, depth and location of the lesions. Options include:

• Excision: This is a surgical approach and is appropriate for some types of skin cancer. The doctor cuts out the cancer and 4 to 6 millimeters of surrounding tissue, depending on the cancer type. Cancer is successfully removed about 95 percent of the time when this technique is used appropriately.
• Mohs surgery: The doctor removes the cancer layer by layer until all cancer cells are gone. During the surgery, each newly removed layer is examined under the microscope to check for cancer cells before proceeding. This exacting process avoids the removal of healthy tissue. The surgery was developed Dr. Frederick Mohs at the University of Wisconsin in the 1930s and requires specialized training. The cure rate, as high as 99 percent for some specific forms of skin cancer, makes this an excellent treatment. This technique is most commonly used to treat skin cancer on the head and neck.
• Cryotherapy: For precancers, liquid nitrogen is used to freeze precancer cells. The cure rate is 90 to 95 percent.
• Laser therapy: A focused beam of light vaporizes cancer cells, with little damage to surrounding tissue. This is appropriate for superficial skin cancers only.
• Curettage followed by electrodesiccation or cryotherapy (freezing): The doctor removes most of the growth and then scrapes cancer cells with a circular blade called a curet. Any remaining cancer cells are destroyed with an electric current or cryotherapy.
• Photodynamic therapy: A substance that makes the skin sensitive to light is applied to the skin cancer and allowed to set for several hours. Then the area is exposed to a special type of red or blue light, which activates the sensitizing substance causing destruction of the cancerous cells. This is used for superficial types of skin cancer.
• Radiation: Radiation can be used for inoperable skin cancers. Cure rates are acceptable when done by an experienced physician. However, radiation puts the patient at risk for future nonmelanoma skin cancers, so it should be used with caution. Some aggressive skin cancers treated surgically may require adjuvant radiation treatment for the best cure rate.
• Creams: Some prescription creams have been proven effective for certain types of skin cancer. They are an option for patients who aren't candidates for surgery because of other health concerns. Efficacy is 60 to 80 percent.

Early detection of skin cancer is important. If you have a number of moles, you need a full skin exam by a dermatologist with follow up based on their recommendations. If you have a persistently red, scaly area that doesn't resolve, a sore that is non-healing or a spot that bleeds with gentle trauma (such as while drying with a towel), you also should see a dermatologist.

Other warning signs for a specific type of skin cancer, melanoma, include moles that are: asymmetrically shaped; have a border that's notched, scalloped, or otherwise irregular in shape; non-uniform in color; larger than one-fourth inch across; or changing or growing.

Of course, the best way to deal with skin cancer is prevention. But don't rely on sunscreen alone to protect you and don't abuse the benefits of sunscreen by staying out in the sun for long periods. Think of sunscreen as a supplement to other measures to protect yourself from UV radiation. Wear protective clothing, such as a wide-brimmed hat and tightly woven clothes to protect your arms and legs.

Here's another tip that you may not have heard. Rit SunGuard is a laundry additive that increases sun protection of clothing. A typical, lightweight T-shirt doesn't offer much sun protection, perhaps equivalent to SPF 4 to 8. SunGuard or similar products increase the sun protection of clothing to SPF 50 or 60.

-- Leslie Christenson, M.D., Dermatology, Mayo Clinic, Rochester, Minn.