High-Risk Melanomas Often on Head or Neck
Rate of cell growth may be a key to diagnosis and treatment, an expert says
By Steven Reinberg
WEDNESDAY, Aug. 20, 2014 (HealthDay News) -- The speed at which cancer cells grow may help doctors diagnose and treat the most aggressive melanomas, researchers say.
Using this measure, investigators have found that the deadliest skin cancers occur most often on the head and neck of older men with a long history of sun exposure.
These lesions also grow quickly and are often colorless, the researchers discovered.
Rapid cell growth -- called "high mitotic rate" -- is associated with poorer prognosis in patients with melanoma. For this new study, the Australian research team examined the physical characteristics of melanomas and their rate of cell division to help doctors know how to spot these faster-growing cancers.
Currently, the seriousness of a melanoma is established by its depth. "Now we might add the mitotic rate as part of that prognostic factor," said Dr. Doris Day, a dermatologist at Lenox Hill Hospital in New York City, who had no part in the study.
"You would expect that cells that are dividing faster make for more aggressive melanomas that are going to have a worse prognosis," said Day.
That most of these aggressive cancers were found on exposed areas of men with significant sun histories indicates that prolonged exposure to sunlight increases the odds of having more aggressive melanomas, Day noted.
"It makes me worry about all these young women who go to tanning salons, because of their chronic exposure," Day said. "I'm worried that 20 or 30 years from now we are going to see these women developing this worse type of melanoma."
In the United States, about 9,000 people die of melanomas of the skin each year, according to the U.S. Centers for Disease Control and Prevention.
Day said the key to treating melanoma is diagnosing it early.
Perhaps melanomas with high mitotic rates will be treated differently than those with lower rates, she added.
"We may now get more aggressive in the treatment of melanoma that is not deep but has a high mitotic rate. Instead of just cutting it out, we may add in chemotherapy," she said. "So we may change how we evaluate melanomas and how we treat them."
But before mitotic rate can be used as a predictor of the aggressiveness of melanomas, the results from this study will have to be duplicated, Day said.
Another expert, Dr. Homere Al Moutran, of Staten Island University Hospital in New York City, agreed. "Mitotic rate, even though not universally evaluated for melanoma, has been shown to be a significant prognostic indicator in skin cancer," he said.
The American Academy of Dermatology says inclusion of mitotic rate in skin cancer reports is an option, he noted. "This study shows a possible particular behavior for mitotically active melanoma, but more studies are needed to define whether mitotic rates should become a standard independent factor in these tumors," Al Moutran said.