The findings, published in the Journal of Clinical Oncology, support earlier research showing that women are less likely to die from melanoma, the deadliest of the skin cancers.

Researchers suggested that biological differences between the sexes might influence how the body deals with the cancer, although a definitive explanation on the better outcome for women remains uncertain.

Lead author Arjen Joosse, who is completing his PhD at Erasmus University Medical Center in Rotterdam, the Netherlands, and his team looked at four clinical trials that melanoma patients had joined.

The more than 2,600 study participants were followed for two to 12 years. Over time, 366 of the men and 267 of the women died.

This meant 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.

"Our first conclusion is indeed it's something biological," Joosse told Reuters Health.

Earlier studies had hinted that behaviors explained the differences between men and women - such as women being perhaps more likely to visit their doctor after noticing changes on their skin, and being diagnosed with cancer earlier as well as having thinner tumors.

But even when the researchers took into account the thickness of the tumors, they found that women still had a 30 percent advantage over men in the progression of the disease.

"Once somebody has melanoma, we absolutely believe that men and women deal with it differently, in general," said 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, who was not involved in the study.

The obvious potential explanation was estrogen, Joosse said - but 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 younger women have over younger men.

But older women still held to their advantage, the group said, adding that more research is needed.

Sondak said genes might have something to do with Joosse's findings, adding 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," he said. SOURCE: bit.ly/Imd61t

(Reporting from New York by Kerry Grens at Reuters Health; editing by Elaine Lies and Bob Tourtellotte)

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