Increased Prevalence of Left-sided Skin Cancer: A Systematic Review and Meta-analysis / 대한피부과학회지

ABSTRACT

BACKGROUND: Based on trends demonstrated in the United States, a very insignificant number of people have shown a predisposition to left-sided skin cancer. However, to date, no systematic review or meta-analysis has demonstrated the predominance of left-sided skin cancers over right-sided skin malignancies. OBJECTIVE: We systematically reviewed and meta-analyzed all data pertaining to locations of skin cancers. METHODS: All data were pooled using the Mantel-Haenszel method (random-effects weighting); an inverse variance model featuring fixed-effects weighting was applied to explore the robustness of modeling. Heterogeneity was evaluated using the I2 test. Dichotomous outcomes with respect to the prevalence of left- and right-sided skin cancers are presented as relative risks (RRs) with 95% confidence intervals (CIs). RESULTS: Nine studies were included in our evaluation. Our study sample included 182,840 patients with malignant melanoma (MM), 1,419 patients with basal cell carcinoma (BCC), and 331 patients with squamous cell carcinoma (SCC). Meta-analyses of pooled observational data revealed greater prevalence of left-sided MM compared to right-sided MM (RR 0.91, 95% CI 0.89~0.92, p<0.01), while left-sided SCC was more prevalent than right-sided SCC (RR 0.83, 95% CI 0.71~0.97, p=0.02). However, right-sided BCC was more prevalent than left-sided BCC (RR 1.07, 95% CI 0.95~1.19, p=0.26). CONCLUSION: Observational studies vary greatly in terms of design, methodological quality, and types of patients studied. Of note, only a few studies analyzing BCC and SCC were included in our present meta-analysis. Additionally, a selection and reporting bias could have affected our results. Our meta-analysis suggests that both MM and SCC demonstrate a left-side bias, but BCC does not.