A large study involving almost 26,000 men surveyed over a decade has found evidence of a link between an almost-doubling of the incidence of the potentially-lethal skin cancer, melanoma, and use of the ED drug, Viagra (Pfizer s sildenafil).
Researchers led by Wen-Qing Li, Ph.D., of the Harvard Medical School-Brigham and Women s Hospital, analyzed the vast troves of data available from the Health Professionals Follow-up Study which began in 1986 and has input on over 51,000 male health professionals, initially aged 40-75 then. Beginning in 2000, the survey included questions about ED and drugs for it (which was only Viagra then). Also on the survey already were questions about risk factors for melanoma, including prior history, moles, hair color, and sun exposure/sunburn history. The final report is based on responses from 25,848 men, average age 65.
The study s results, which were reported in this week s JAMA Internal Medicine, show that 5.8 percent of the sample acknowledged some use of sildenafil recently, and 6.3 percent said yes to any use. One-hundred forty-two malignant melanomas (MM) were diagnosed during the study period, and recent sildenafil (S) use at baseline was associated with a 1.84 increased risk of MM an impressive near-doubling of the risk, after the authors controlled for multiple potential confounders. There was no link to any other form of skin cancer, the much-less-dangerous basal and squamous cell types.
A commentary in the same journal by JAMA editor and Northwestern University Dermatologist Dr. June Robinson, explains (or attempts to) the proposed biological pathway for S to enhance MM risk, via a complex series of enzymatic up-regulations dependent upon certain genetic mutations known to be relatively frequent in MM cells (BRAF and NRAS, if you must know).
She also supplies these cogent stats:
In 2014, about 76 100 new melanomas will be diagnosed, and an estimated 9710 persons will die (about 6470 men and 3240 women). Patients with melanoma in situ, stage 0, have a 5-year survival rate of 99% when treated with excision, whereas those with melanoma limited to the skin and with a tumor thickness of 2.01 to 4.0 mm, stage II B, have a 5-year survival rate of about 57%. Patients with metastatic melanoma, stage IV, have a 5-year survival rate of 15% to 20%. Despite newly available targeted agents, systemic therapies rarely lead to cures. These sizable survival differences illustrate the need for early detection of melanoma; early detection of primary melanomas followed by surgical excision remains critical.
ACSH s Dr. Gil Ross had this comment: Preventing MM by avoiding excessive sunlight is a key factor, as we have said on numerous previous occasions. Might avoiding Viagra also be prudent for older men; alternatively, if that price seems too dear, extra attention to avoiding sunlight exposure as well as getting a full-body mole examination should be emphasized as well. (and NOTE: if this rationale regarding Viagra-S holds true, other similarly-acting ED drugs will also be found to be of concern)
However, before jumping with both feet into the Be afraid of Viagra camp, Dr. Robinson suggests you all pay attention to this inconvenient counter-argument:
From 1975 through 1986, the annual percentage increase in men s age-adjusted incidence rate of melanoma was 5.6%. This slowed to 2.4% per year from 1992 to 2010.1 Sildenafil received approval for the treatment of erectile dysfunction on March 27, 1998.3 The rate of increase in melanoma in men slowed as sildenafil came into use, which raises a cautionary note about the influence of sildenafil in the development of melanoma, but its role in the biologic behavior of melanoma in older men warrants further study.