MELANOMA MORE DEADLY IN MALES 

The rates of mortality from melanoma are higher in males in their teenage and young adult years than in females of similar ages, according to a study published online today in JAMA Dermatology.

This difference in mortality between the sexes could mean that there is a fundamental biologic difference in male and female melanoma, the authors of an accompanying editorial suggest.

In a population-based cohort study that analyzed data from the Surveillance, Epidemiology, and End Results (SEER) network of cancer registries for melanomas diagnosed from January 1, 1989 to December 31, 2009, researchers found that young men were 55% more likely to die of melanoma than age-matched women.

The finding held true despite adjustment for factors typically associated with poor prognosis, such as tumor thickness, histology, location of the melanoma, and the presence and extent of metastasis.

"Studies worldwide have demonstrated that women diagnosed with melanoma tend to fare better than men in terms of improved survival. This has mostly been attributed to better screening practices and behaviors in women that result in thinner, more curable tumors, and also to more frequent physician visits in older individuals that result in earlier detection," senior author Susan Swetter, MD, from the Stanford University Medical Center, Palo Alto, California, told Medscape Medical News.

To investigate sex disparities in survival in younger people, Dr. Swetter and her research team, identified 26,107 non-Hispanic white adolescents and young adults, aged 15 to 39 years, with a primary invasive melanoma of the skin.

The subjects were followed for an average of 7.5 years, and 1561 melanoma-specific deaths were recorded.

Although overall there were fewer melanoma cases in young males (40%) than in young females, 64% of the deaths from melanoma were in males.

Not only were males more likely to die of melanoma than females (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.39 - 1.73), they were also more likely to die within each age group assessed (15 to 24, 25 to 29, 30 to 34, and 35 to 39 years).

Even males with thin melanomas (≤1.00 mm) were twice as likely to die as age-matched females (HR, 1.95; 95% CI, 1.57 - 2.42).

In a subanalysis, adjustment for health insurance and socioeconomic status did not significantly alter these results.

"Our findings are particularly timely because a 2012 pooled analysis of 4 European Organization for Research and Treatment of Cancer (EORTC) phase 3 trials found that women with melanoma had a 30% survival advantage, compared with men, despite similar clinical follow-up and treatment through randomized trials," Dr. Swetter noted (J Clin Oncol. 2012;30:2240-2247).

A more recent European analysis demonstrated a persistent, independent female survival advantage, even in patients with advanced melanoma, although most patients in these studies tended to be older, she added.

"Our results present further evidence that a biologic mechanism may contribute to the sex disparity in melanoma survival, particularly since adolescents and young adults see physicians less frequently and are less likely to have sex-related behavior differences in skin cancer screening practices than older individuals," Dr. Swetter said.

Males should definitely become the object of skin cancer prevention campaigns, she said.

"Many recent public health messages have focused on primary prevention of melanoma in teenaged and young adult women through tanning-bed avoidance. We need to send a similar message to adolescent and young adult males, emphasizing that they tend to do worse with melanoma. This may help to promote early detection of any new or changing skin lesion and enhance their chances for cure," Dr. Swetter explained.

Biologic Explanation for Sex Difference?

In their accompanying editorial, David E. Fisher, MD, PhD, from Harvard Medical School, and Alan C. Geller, MPH, RN, from the Harvard School of Public Health, in Boston, Massachusetts, write that "if a biological explanation underlies the sex differences reported herein, it adds to the growing evidence that melanoma is multiple distinct diseases."

They note that it is "notable" that the newly diagnosed melanomas in men were, on average, thicker and more advanced than those in women.

"This leads to the question of whether increased mortality may have arisen from diagnostic challenges such as 'missed' deep margins or later diagnosis and delay," they write.

However, "even for melanomas deeper than 4 mm, men fared more poorly than women, thereby pointing more in the direction of distinctive biology," they note.

The editorialists stress, however, that whatever the cause of the disparity in deaths from melanoma, both sexes have better overall survival if the melanomas are diagnosed at an earlier stage.

They agree with Dr. Swetter and her colleagues that awareness about melanoma and early diagnosis should be promoted in young men.

"Hopefully, studies such as the one reported herein can prompt primary care physicians of young at-risk men to carefully screen their patients and counsel them to perform monthly skin self-examinations," the editorialists conclude.

The authors have disclosed no relevant financial relationships. The editorial was supported in part by grants from the National Institutes of Health.

JAMA Dermatol. Published online June 26, 2013. Abstract, Editorial