Left-Sided Excess of Melanoma Occurrence but Not of Other Skin Cancers: Additional Evidence

The document discussed the observation of a left-sided predominance of melanoma occurrence, as confirmed by multiple studies, including a large population-based study by Dores et al. This left-sided excess was noted for melanoma but not for other skin cancers, such as squamous cell carcinoma and basal cell carcinoma, where no significant laterality was found. The findings suggested that asymmetrical sun exposure during vehicle driving was unlikely to explain the laterality, as the pattern was consistent across countries with different driving orientations. The document proposed that the left-sided excess of melanoma might be due to asymmetries in embryonic development of melanocytes or the angiolymphatic system, and it called for further research into melanoma precursor lesions to better understand this phenomenon.