KYOTO, JAPAN — Does regular use of aspirin or other NSAIDs protect against melanoma?
The question remains open following the presentation of two large, well-controlled studies at a meeting of the European Society for Dermatological Research, the Japanese Society for Investigative Dermatology, and the Society for Investigative Dermatology.
Epidemiologic studies have showed NSAID-associated reductions in the incidence and mortality of breast, co-lorectal, and prostate cancers. But there has been little work looking at NSAIDs and melanoma. A track record of favorable observational studies is generally a prerequisite to organizing a large randomized placebo-controlled intervention trial for cancer chemoprevention.
Dr. Clara Curiel-Lewandrowski presented a case-control study involving 400 cutaneous melanoma patients and 600 controls matched for gender, age, and neighborhood.
There was no indication that long-term use of statins reduced melanoma risk, said Dr. Curiel-Lewandrowski of Harvard Medical School, Boston. But the prevalence of a history of more than 5 years’ duration of NSAID use, regardless of frequency, was 18% in melanoma patients, versus 24.2% in controls. After adjustment for baseline melanoma risk factors, this translated into a 27% relative risk reduction in conjunction with more than 5 years of NSAID use. Specifically, more than 5 years of aspirin use was reported by 13.3% of the melanoma group and 21.2% of controls, for an adjusted 44% relative risk reduction.
The possibility that nonaspirin NSAIDs also have a chemopreventive effect could not be excluded. The numbers of participants on any given NSAID other than aspirin were not large enough to draw conclusions.
In a separate presentation, Dr. Maryam M. Asgari presented a prospective cohort study involving 63,809 participants in the National Institutes of Health-sponsored Vitamins and Lifestyle (VITAL) study. On a questionnaire, participants self-reported NSAID consumption during the prior 10 years and listed melanoma risk factors, including family history, a personal history of three or more severe sunburns during ages 10-20, having had moles removed, and red or blond hair.
During an average follow-up of 5 years, 349 new cases of melanoma occurred. After adjusting for melanoma risk factors as well as indications for NSAID use, investigators found no association between melanoma risk and overall use of NSAIDs, duration of use, or dosage.
NSAID use did not influence tumor invasion, Breslow Depth, or risk of metastasis, said Dr. Asgari, a dermatologist and Moh's surgeon in the division of research at Kaiser Permanente, Oakland, Calif.
Audience members said the rate of NSAID use in VITAL study struck them as high—63% indicated they had used an NSAID at least once per week for a year—and the melanoma incidence seemed low.
Dr. Asgari replied that the VITAL cohort was 50-75 years old, an age when NSAID use typically expands. As for the low incidence of melanoma, the study was conducted in western Washington, which has one of the lowest melanoma rates in the U.S., she added. The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Cancer Institute.