Seasonal pattern of the diagnosis of cutaneous melanoma: a hospital-based study in a Mediterranean country

BACKGROUND: Several investigators have described a seasonal variation in the diagnosis of cutaneous melanoma. Limited data exist on the seasonality of melanoma diagnosis in Southern European countries. PATIENTS AND METHODS: The seasonal pattern of diagnosis was analyzed in 404 Greek patients diagnosed with cutaneous melanoma (CM) between 1996 and 2004. A summer-to-winter ratio was determined overall and in relation to gender, age, anatomic site, histopathologic type, and tumor thickness. RESULTS: The summer-to-winter ratio was 1.53 for all patients (95% CI [confidence interval]: 1.15-2.02) with a ratio of 1.83 for women (95% CI: 1.20-2.78) and 1.28 for men (95% CI: 0.87-1.88). A seasonal pattern of melanoma diagnosis was observed for patients younger than 50 years of age (1.70, 95% CI: 1.05-2.74) and between 50 and 69 years (1.64, 95% CI: 1.05-2.56), for melanoma located on the upper or lower extremities (2.50, 95% CI: 1.12-5.56 and 2.23, 95% CI: 1.19-4.18, respectively), for superficial spreading and nodular melanomas (1.73, 95% CI: 1.12-2.69 and 1.52 95% CI: 0.96-2.41) and for melanomas with a tumor thickness of 1-2 mm (1.69, 95% CI: 0.91-3.12) and > 4 mm (2.13, 95% CI: 1.04-4.35). CONCLUSIONS: No major differences were seen in the seasonal distribution of CM diagnosis in a Mediterranean population compared to previously reported results. A better ascertainment of the skin during the summer and an increased awareness due to the melanoma screening campaigns are the more likely reasons for the seasonality of melanoma diagnosis in Greece.