Skin cancer risk may vary according to sexual orientation and gender identity, two new studies suggest.

An analysis of survey data from more than 800,000 U.S. adults found skin cancer may be more common among gay and bisexual men and people who are gender non-conforming, researchers report in JAMA Dermatology.

"We need to understand what is driving (this increased risk), why these groups are more susceptible and what could be done to reduce the risk," said Dr. Arash Mostaghimi, director of dermatology inpatient consultation at Brigham and Women's Hospital in Boston.

Other studies have shown that gay and bisexual men have higher rates of tanning salon use, Mostaghimi said. But there are other possible causes for higher rates of skin cancer in these groups, he added.

"There might be a biological reason, or there might be differential exposures" such as to human papillomavirus (HPV), Mostaghimi said. "HPV is thought to be linked to squamous cell cancer in certain populations."

Both of the new papers were written by Mostaghimi and his colleagues: one focused on skin cancer and sexual orientation, the other on skin cancer and gender identity. Both analyzed data from the 2014 to 2018 Behavioral Risk Factor Surveillance System questionnaires, a national system of telephone surveys done under the auspices of the Centers for Disease Control and Prevention.

The study on sexual orientation included data from 845,264 men and women, including individuals identifying themselves as heterosexual, gay, lesbian or bisexual. In this study, compared to heterosexual men, gay men were 26% more likely to have a lifetime history of skin cancer and among bisexual men, the odds were 48% higher. Compared to heterosexual women, lesbian women had about the same chances of having had skin cancer, and among bisexual women it was 22% less common.

The study on gender identity included 864,197 adults, including cisgender men and women (whose gender identity aligns with the gender assigned at birth), transgender men, transgender women and gender nonconforming individuals (GNC).

Compared with the rate in cisgender men, skin cancers were 15% less common in cisgender women, but more than twice as common among GNC individuals.

"The GNC finding was a bit of a surprise," said Mostaghimi. "We would really like to explore that further to find out why gender nonconforming individuals might have a higher rate of skin cancer."

Dr. Diwakar Davar welcomed the focus on sexual and gender minorities.

This study is trying to tease apart the role of sexual orientation and gender identity on cancer prevalence, said Davar, a medical oncologist/hematologist at the UPMC Hillman Cancer Center in Pittsburgh.

"Outside of HIV clinics that's not something that physicians consider," Devar said. "It's a very important thing in cancer treatment. If you don't understand this very important personal issue, you might not be able to build a rapport with the patient and that might affect the patient's ability to follow through with treatment."

Because the data were self-reported, the findings aren't as strong as they might be, said Dr. Hooman Khorasani, chief of the division of dermatologic and cosmetic surgery at the Icahn School of Medicine at Mount Sinai in New York City.

Still, Khorasani said, reports show gay men tend to use tanning beds more often than heterosexual men. Moreover, rates of HIV are higher in gay men than in heterosexual men and that might put them more at risk for skin cancer, he added.

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