CUTANEOUS MALIGNANT-MELANOMA IN SOUTHERN SWEDEN 1965, 1975, AND 1985 - PROGNOSTIC FACTORS AND HISTOLOGIC CORRELATIONS

BACKGROUND. There is a worldwide increase in the incidence of cutaneou s malignant melanoma (CMM) among whites. In Sweden, a five-fold increa se has been recorded since 1960, although the increase in mortality ra te is substantially lower. Tumor thickness is recognized as the most i mportant histologic prognostic factor for primary melanoma. In a previ ous study, the authors did not find any significant decrease in mean t umor thickness over the period 1965-1985 in their region. In the curre nt study, prognostic factors for melanoma were evaluated for this time period. METHODS. In a population-based study, 468 cases of invasive m elanoma, diagnosed in the years 1965, 1975, and 1985, were histopathol ogically reexamined. The level of invasion, tumor thickness, regressiv e reaction, ulceration, presence of inflammatory cells, presence of be nign nevus cells, and site of presentation were studied. In 461 of the se 468 patients, it was possible to correlate the histopathologic fact ors with survival. RESULTS. In univariate analyses, the parameters of presence of ulceration, increasing tumor thickness, male gender, nodul ar type of melanoma, and older age at diagnosis were significantly rel ated to a shortened overall survival. In various multivariate models w ith adjustment for age and the factors studied simultaneously, ulcerat ion, increasing tumor thickness, and male gender were significantly as sociated with a poor prognosis. Correlations between the factors studi ed were noted. It was observed that older patients tended to have thic ker tumors. Thick melanomas correlated to a deeper level of invasion ( Clark's), nodular growth pattern, ulceration, less inflammation, and l ess regression compared with thin, less invasive melanomas. Women had significantly fewer inflammatory cells and fewer signs of regression i n their tumors compared with men. CONCLUSIONS. In multivariate analyse s adjusted for age, increasing tumor thickness, older age, ulceration, and male gender were significantly associated with a poor prognosis a mong patients with invasive CMM. None of these factors showed a signif icant change for the years 1965, 1975, and 1985. Thus, a change in the prognostic factors studied does not explain the increased survival of melanoma patients for this time period. (C) 1997 American Cancer Soci ety.