Use of topical sunscreen and the risk of malignant melanoma. Results of a meta-analysis of 9,067 patients.

PURPOSE: Prior epidemiological studies suggest that the use of sunscreen preparations is associated with increased risk of cutaneous malignant melanoma (CMM) although the data are conflicting. A meta-analysis was performed to evaluate this suspected association.METHODS: A protocol was developed for a meta-analysis examining the association between frequent sunscreen use versus non-use and the development of CMM. Data from observational studies were pooled using a general variance based meta-analytic method employing confidence intervals. The outcome of interest was a summary relative risk (RRs) reflecting the risk of melanoma associated with sunscreen use versus non-use. Sensitivity analyses were performed when necessary to explain any observed statistical heterogeneity.RESULTS: Eleven case-control studies enrolling 9,067 patients were combined in a meta-analysis. This yielded a RRs of 1.11 (CI = 0.37-3.32), a non-statistically significant result, (i.e. no association between sunscreen use and melanoma risk). Since the data were found to be heterogeneous, i.e. Q = 42.0 (p < 0.001), a series of sensitivity analyses were performed to explore possible sources of heterogeneity. Stratifying studies based on study design, i.e. hospital based versus population based, showed that hospital derived data were highly heterogeneous (Q = 36.9, p < 0.001) while the population registry data were not (Q = 4.9, p = 0.18). Combining those studies using population based data gave a RRs of 1.01 (95% CI = 0.46-2.28) indicating no association between sunscreen use and the development of CMM.CONCLUSIONS: The available epidemiological data do not support the existence of a relationship between topical sunscreen use and an increased risk of CMM.