Invasive cutaneous malignant melanoma in Sweden, 1990-1999. A prospective, population-based study of survival and prognostic factors.

BACKGROUND: The objective of the current study was to compile prospective, population-based data on cutaneous invasive melanomas in Sweden during the period from 1990 to 1999, to describe and analyze survival data and prognostic factors, and to make comparisons with previously published Swedish and international data. METHODS: Twelve thousand five hundred thirty-three patients, which included 97% of all registered melanomas in Sweden, were included and described. Among these, 9515 patients with clinical Stage I and II melanoma were included in an analysis of survival and in a univariate analysis, and 6191 patients were included in a multivariate analysis of prognostic factors. RESULTS: There was no significant change in melanoma incidence during 1990-1999. Favorable prognostic factors were found, especially in younger and female patients, resulting in a relative 5-year survival rate of 91.5%. In the multivariate analysis, significant factors that had a negative effect on survival were Clark level of invasion, Breslow thickness, ulceration, older patient age, trunk location, greatest tumor dimension, nodular histogenetic type, and male gender. CONCLUSIONS: During the period from 1990 to 1999, the 5-year survival of patients with malignant melanoma in Sweden was better compared with the previously reported rates in published, population-based studies from Sweden, probably as a result of better secondary prevention due to better knowledge and awareness by both patients and the medical profession. The more favorable prognostic factors and the change in melanoma location found in younger patients, compared with earlier reports, may reflect changes in clothing as well as tanning habits; however, a decrease also was found in Clark Level II and thin melanomas for the same patient group. The authors concluded that further improvements can be achieved with better access to health care and with the use of early melanoma detection campaigns.