In contrast to some earlier reports, in this large study, low-dose aspirin seemed to usefully reduce melanoma risk.
Melanoma incidence is increasing, and safe, effective methods of prevention are highly sought. Whether nonsteroidal anti-inflammatory drugs (NSAIDs) confer any benefit as chemopreventive agents is controversial. A study of 92,125 Caucasian women in the Nurses’ Health Study did not find reduced risk for melanoma with NSAID use (Cancer Causes Control 2012; 23:1451), and other large studies showed only marginal benefits or none. Aspirin has been demonstrated to lower the risk for gastric, colorectal, and breast cancers; its role as a preventive agent for melanoma has not been adequately studied.
Using data from the Women’s Health Initiative Observational Study (WHI OS), these authors studied the association between NSAID use and cutaneous melanoma risk in postmenopausal women. Melanoma diagnosis was adjudicated by confirmation of pathology reports and medical record review. Just under 60,000 women were eligible for inclusion, and median follow-up was 12 years.
Of 548 incident melanomas in these women, 289 were in situ, 255 were invasive, and 4 could not be classified. The melanoma incidence rate was 21% lower in aspirin users than in those taking nonaspirin NSAIDs or those not taking NSAIDs. In women taking aspirin for 5 or more years, the risk of developing melanoma was 30% lower. There was no benefit on melanoma risk from acetaminophen use. The vast majority of melanomas (94%) developed in patients without a prior history of melanoma.
Among the limitations of this study are that medication use was self-reported, and that information on family history of melanoma and on hair and eye color was lacking. Strengths of the study include detailed information on skin type, sun-exposure and sun-protection habits, and prior history of skin cancer. Additional pluses are the large cohort with geographic diversity, long follow-up, and relatively large number of confirmed melanoma cases.
Comment: This is an important finding. One wonders whether these observations might hold true for pre- and perimenopausal women, other ethnic groups, or men. The primary risk from daily low-dose aspirin is gastrointestinal bleeding. There is clear evidence that low-dose daily aspirin is beneficial for the prevention of colorectal cancer in Lynch syndrome. Unless there is a contraindication, I will tell a patient who asks my advice that low-dose aspirin seems to usefully reduce melanoma risk. Left unstated in this study was whether aspirin users who developed melanomas had a difference in lesion thickness.
— Jeffrey P. Callen, MD in Journal Watch Dermatology