Clinical and histopathological characteristics in relation to aetiological risk factors in cutaneous melanoma:: a population-based study

In this population-based, case-control study from Sweden using data collected from 1988 to 1990, an increased risk of melanoma was associated with the number of sunburns, propensity to freckle, the number of raised naevi and a family history of melanoma. Furthermore, a decreased risk was associated with occupational sun exposure. The purpose of this study was to investigate whether different histopathological features of the melanoma and clinical factors were related to the different aetiological risk factor patterns. All the confirmed primary cutaneous melanomas(n = 366) were included in the study. Both univariate analyses with tests for interaction and multivariate analyses were performed. Patients with melanoma on the trunk and patients with thin melanomas had an excess of close relatives with a history of melanoma (odds ratios [ORs] = 2.7 and 2.3, respectively). A relationship was also seen between melanomas in younger persons and a family history of melanoma (OR=2.6). The presence of raised naevi on the arm had a tendency to be closer related to melanoma of the nodular type (OR=4.3) than melanoma of the superficial spreading type (OR=1.6). Patients with outdoor occupations during summer had a decreased risk of developing melanoma on the extremities. Melanoma diagnosed in patients born before 1939 had an association with sunburns (OR=1.9) and freckling (OR=2.0), while melanomas in patients born in 1939 or later were related to a family history of melanoma (OR=2.2). These results suggest that different histopathological and clinical features of melanoma are associated with different risk factor patterns, which may imply diverging tumour genesis. (C) 1999 Lippincott Williams & Wilkins.