Skin melanoma in Italy: a population-based study on survival and prognostic factors.

Survival and prognostic factors of invasive cutaneous melanoma patients diagnosed in the province of Florence, Italy, were studied using a regression analysis of relative survival rates. The case series consisted of 428 patients reported by the Tuscany Cancer Registry between 1985 and 1989. The effect of gender, age, anatomical site, histological type and microstaging parameters upon relative survival were evaluated using an extension of the Cox proportional hazard model. Five-year relative survival was 70%; 8-year relative survival, referring to a subset of patients, was 67%. In univariate analysis, the following variables were significantly associated with better prognosis: female gender, age younger than 60 years, superficial spreading melanoma (SSM) compared with nodular melanoma (NM), location on the limbs, a thinner lesion according to Breslow, a shallower Clark level. Females had a clear-cut prognostic advantage over males in each category of the variables considered above. After simultaneous adjustment for all other variables, three factors continued to show an independent prognostic effect: age, gender and microstaging parameters (Breslow thickness and Clark level, separately fitted in the model). In the multivariate analysis, the prognostic advantage of females over males was specifically seen for lesions located on the trunk and for both SSM and NM histotype.