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NEW YORK (Reuters Health) - Women diagnosed with melanoma are more likely to survive the skin cancer than men and less likely to have it recur, according to a new study.
The researchers suggest that biological differences between the sexes might influence how the body deals with the cancer, although a definitive explanation for women's better outcomes remains uncertain.
The findings support earlier research showing that women are less likely to die from melanoma, the deadliest of the skin cancers.
According to the U.S. Centers for Disease Control and Prevention, 21 out of every 100,000 people are diagnosed with melanoma each year, and close to three out of 100,000 will die of the disease.
"Once somebody has melanoma we absolutely believe that men and women deal with it differently, in general," said Dr. Vernon Sondak, chair of the department of Cutaneous Oncology at Moffitt Cancer Center and a professor at the University of South Florida College of Medicine in Tampa, who was not involved in this study.
To try and answer the question as to why women do better, the European research team looked to four clinical trials that melanoma patients had joined.
These included more than 2,600 people with earlier stages of melanoma.
The study participants were followed for two to 12 years.
Over time, 366 of the men died and 267 of the women.
This meant that women were 30 percent less likely to die from any cause during the time studied, and also about 30 percent less likely to die from the melanoma than men.
They were also 30 percent less likely to have a relapse of the cancer.
IS ESTROGEN RESPONSIBLE?
Dr. Arjen Joosse, the lead author of the study, who is completing his PhD at Erasmus University Medical Center in Rotterdam, the Netherlands, said that earlier studies have hinted that behaviors explain the differences between men and women.
Women are perhaps more likely to visit their doctor after noticing changes on their skin, which would lead to women being diagnosed with cancer earlier and having thinner tumors.
To account for earlier diagnosis making the survival rates look better, Joosse and his colleagues took into account the thickness of the tumor, and they still found that women had a 30 percent advantage over men in the progression of their disease.
"Our first conclusion is indeed it's something biological," Joosse told Reuters Health.
The obvious potential explanation that sprung to mind was estrogen, Joosse said.
If estrogen were responsible, then post-menopausal women, who have low estrogen levels, should have a smaller advantage over men in their age group than the advantage younger women have over younger men.
But the researchers report in their study in the Journal of Clinical Oncology that older women still held on to their advantage over older men, leaving estrogen as an unlikely explanation.
Joosse said his study couldn't determine the real cause of the differences, and he said future work in the laboratory and in research animals should look for the biological role.
Sondak said that genes might have something to do with Joosse's findings.
He added that because the causes of men's poor melanoma outcomes are unknown, stressing the behaviors that are known to prevent cancer and promote earlier detection are important.
"Behavior is something we can modify. Awareness is something we can increase. Genes are a little harder to change," Sondak told Reuters Health.
He urged people to protect their skin from the sun and avoid tanning salons, efforts that are helpful to reduce the risk of skin cancer in both men and women.
Sondak said that while women are less likely to die of melanoma, they should still take the cancer seriously.
"We would never want the message to be, 'women should not worry about melanoma because they do better than men,'" he said. On the contrary, skin cancer is something everyone should worry about, said Sondak.
SOURCE: bit.ly/Imd61t Journal of Clinical Oncology, online April 30, 2012.