Regular Sunscreen Use May Reduce Invasive Melanoma Risk
Adapted from the NCI Cancer Bulletin.
Regular sunscreen use may reduce the risk of developing melanoma, according to results of a randomized controlled trial that were reported December 6, 2010, in the Journal of Clinical Oncology. The trial is the first prospective, randomized study to investigate the link between sunscreen use and melanoma, the most deadly type of skin cancer.
Researchers led by Adèle Green, Ph.D., of the Queensland Institute of Medical Research examined the incidence of melanoma among 1,621 white adults in a township in Queensland, Australia. They divided the study participants, age 20 to 69, into two groups. From 1992 to 1996, the participants in one group were given an unlimited supply of a broad-spectrum sunscreen with a sun protection factor (SPF) of 16 and were asked to apply it every morning to their head, neck, arms, and hands, and reapply it after heavy sweating, bathing, or long sun exposure. The control group continued using sunscreen of any SPF at their usual discretionary frequency, which for some included no use.
Dr. Green and her colleagues followed the study participants for 10 additional years and tracked all cases of primary melanoma newly diagnosed between 1993 and 2006. They found 11 new cases of melanoma in the daily sunscreen group compared with 22 cases in the discretionary sunscreen group, a 50 percent reduction. Invasive melanoma was reduced by 73 percent in the daily sunscreen group compared with the control group (3 versus 11 cases).
The authors noted that their results are of borderline statistical significance and suggested that their findings for invasive melanoma in particular “should be interpreted cautiously.” Nevertheless, they concluded, “among adults age 25 to 75 years, regular application of SPF 15+ sunscreen in a 5-year period appeared to reduce the incidence of new primary melanomas for up to 10 years.”
In an accompanying editorial, Phyllis Gimotty, Ph.D., and Karen Glanz, Ph.D., of the Center for Clinical Epidemiology and Biostatistics at the University of Pennsylvania School of Medicine wrote: “To our knowledge, the trial’s findings are the first to provide strong evidence for a reduction in the incidence of invasive melanoma after regular application of broad-spectrum sunscreen in adults…. It is unlikely that another trial of comparable scope and rigor will be conducted in the foreseeable future.”
Furthermore, they wrote, although “the question of its efficacy with respect to melanoma prevention should no longer deter scientists or clinicians from recommending sunscreen use,” effective skin cancer prevention should also include avoiding exposure to ultraviolet rays, using clothing to shield skin from the sun, and performing regular skin self examinations.“This study provides important evidence regarding the role of sunscreen use as part of a range of sun-protective behaviors that effectively reduce risk of melanoma,” commented Margaret Tucker, M.D., of NCI’s Division of Cancer Epidemiology and Genetics