Sun exposure, phenotypic characteristics, and cutaneous malignant melanoma. An analysis according to different clinico-pathological variants and anatomic locations (Italy).

OBJECTIVE: The aim of the study was to examine the relation between sun exposure and other selected risk factors and the development of different clinico-pathological variants of cutaneous malignant melanoma (CMM) at different body locations.

METHODS: We analysed data from a case-control study conducted in Italy between 1992 and 1994 on 542 cases of CMM and 538 hospital controls. Clinico-pathological variants included 391 superficial spreading (SSM), 72 nodular (NM) and 39 lentigo maligna (LMM) melanomas.

RESULTS: The risk of SSM increased for a high education level (odds ratio, OR = 1.5, 95% confidence interval, CI, 1.0-2.2), sunburn episodes before age 15 (OR = 1.8, 95% CI, 1.1-2.8), light eye colour (OR = 1.6, 95% CI, 1.1-2.4) and solar lentigines (OR = 1.4, 95% CI, 1.0-1.8). The ORs for total number of nevi >30 were 4.4 (95% CI, 2.9-6.7) for SSM, 5.7 (95% CI, 2.6-12.5) for NM and 2.2 (95% CI, 0.5-9.4) for LMM. The risk of CMM located on the trunk seemed to be higher for a high education level (OR = 1.6, 95% CI, 1.0-2.6) and propensity to sunburn (OR = 1.6, 95% CI, 0.8-3.2). The ORs for sunburn episodes, eye and skin colour, and solar lentigines tended to be higher for CMM located on the face/neck and on the upper limbs than the trunk. Total number of nevi was strongly associated with all anatomic locations.

CONCLUSIONS: Total number of nevi was the major risk factor associated with all melanoma variants and locations. A higher level of education and sunburn episodes in early childhood appeared to be more strongly related to SSM than to other variants.