Malignant melanoma in southern Germany: different predictive value of risk factors for melanoma subtypes

The presented case-control study with 204 melanoma patients and 200 control persons assesses the significance of melanoma risk factors for an ethnically homogeneous population from a geographically small region. In a multivariate analysis of the data the total number of benign naevi proved to be the most predictive parameter with a relative risk (RR) of 14.9 (total number of naevi higher than 50). The constitutional factors red hair colour and skin type 1 were less predictive with an RR of 2.9 and 4.9, respectively. Occupational and recreational sun exposure were of ancillary importance (RR 1.8 and 2.1). The assessment of the risk for the subtypes of melanoma however showed a clear difference in the predictive value of the mentioned risk factors. The risk of developing superficial spreading melanoma is nearly exclusively defined by the number of benign naevi (RR 24.8), red hair colour was of subordinate importance (RR 4.2), whereas the risk of lentigo maligna melanoma is dependent on skin type 1 (RR 12.9) and sun exposure (RR 3.4).