Melanoma
with Gary Cohen, MD
Which region of the world has the highest rate of skin cancer?
Since 1973, the rate of melanoma in the United States has more than doubled. Nearly 8,000 people died of the disease in 2004 alone.
Melanoma is a malignancy of the skin, which may have very serious consequences. Most skin cancers are not very worrisome because they do not have the tendency to spread to other organs. However, according to Dr. Gary Cohen, Director of the Cancer Center at GBMC, “Melanoma has the ability to spread quickly. In its latter stages, this disease is highly resistant to most forms of treatment.” But, thanks to new treatments available through clinical trials at GBMC, the tide may be turning.
Exposure to the sun is by far the leading cause of melanoma. Dr. Cohen says the incidence of the disease increases as you progress south from Maine to Florida, where sun exposure is increased. The highest rates of melanoma are found in Australia and New Zealand because of a hole in the ozone, making exposure to the sun’s ultraviolet (UV) radiation more intense.
One factor that may explain the increased rate of melanoma is the trend toward skimpier swimwear. “In the 1930s, people would wear bathing suits that went below the knees. Consequently, they weren’t as susceptible to skin cancer as we are today,” says Dr. Cohen. He recommends frequently applying sun block with UV protection of at least SPF 24. “Tanning booths should be absolutely off limits,” he adds.
Moles that change in character, get darker, become irregular, or start to bleed, could indicate melanoma, and should be examined by a dermatologist as soon as possible. To determine if it is melanoma, the dermatologist will likely remove the lesion and send it for microscopic evaluation. If melanoma is confirmed, further surgery would be required to obtain a wider margin of normal tissue surrounding the lesion. In some cases, the surgeon may identify a few lymph nodes (the “sentinel” nodes) to determine if the disease has spread.
According to Dr. Cohen, currently the main form of treatment for more advanced melanoma is biologic therapy. The medications used in this treatment are essentially natural cytokines, which are substances secreted by the immune system. However, these drugs are given in much higher doses than the body usually produces. Although they are sometimes highly effective, interferon and interleukin (two common types of cytokines) have low response rates and some undesirable side effects.
The success of these drugs has led cancer researchers to find other ways to boost immunity using cancer vaccines. These vaccines “teach” the patient’s immune system to reject any residual melanoma cells. Although no skin cancer vaccines are ready FDA approval, progress has been made in identifying patients who might benefit from them. In fact, some cancer vaccines are currently being used in clinical trials at GBMC. In addition, improvements continue to be made in the natural immune responses to melanoma cells.
In the past, there has been little enthusiasm for chemotherapy and radiation in treating advanced melanoma because of the resistant nature of this malignancy. However, GBMC is again fortunate enough to actively participate in clinical trials using exciting new drugs and combinations of chemotherapy with targeted agents. “These new treatments are far more specific for cancer cells, leaving normal cells unscathed,” notes Dr. Cohen, “so the new drugs could potentially be much more effective and less toxic.”
The keys to avoiding death from melanoma is prevention using sun block and early diagnosis. “Over 90 percent of patients diagnosed with melanoma are cured when it is found early and the malignancy is removed,” says Dr. Cohen.
