Data from Sun Exposure and Melanoma Survival: A GEM Study

Background: We previously reported a significant association between higher UV radiation exposure before diagnosis and greater survival with melanoma in a population-based study in Connecticut. We sought to evaluate the hypothesis that sun exposure before diagnosis was associated with greater survival in a larger, international population-based study with more detailed exposure information.

Methods: We conducted a multicenter, international population-based study in four countries—Australia, Italy, Canada, and the United States—with 3,578 cases of melanoma with an average of 7.4 years of follow-up. Measures of sun exposure included sunburn, intermittent exposure, hours of holiday sun exposure, hours of water-related outdoor activities, ambient ultraviolet B (280–320 nm) dose, histologic solar elastosis, and season of diagnosis.

Results: Results were not strongly supportive of the earlier hypothesis. Having had any sunburn in 1 year within 10 years of diagnosis was inversely associated with survival; solar elastosis—a measure of lifetime cumulative exposure—was not. In addition, none of the intermittent exposure measures—water-related activities and sunny holidays—were associated with melanoma-specific survival. Estimated ambient UVB dose was not associated with survival.

Conclusion: Although there was an apparent protective effect of sunburns within 10 years of diagnosis, there was only weak evidence in this large, international, population-based study of melanoma that sun exposure before diagnosis is associated with greater melanoma-specific survival.

Impact: This study adds to the evidence that sun exposure before melanoma diagnosis has little effect on survival with melanoma. Cancer Epidemiol Biomarkers Prev; 23(10); 2145–52. ©2014 AACR.