Malignant melanoma. Changing trends in factors influencing metastasis-free survival from 1964 to 1982.

Seven hundred fourteen patients with cutaneous melanoma in clinical Stage I treated between 1964 and 1982 were included in this study. In an analysis of metastasis-free survival, thickness of the tumor, ulceration, gender, epithelioid cells as predominant cells in the tumor, and localization of the tumor were found to be independent prognostic factors. In a time trends analysis, the distributions of three of the prognostic factors (thickness of the tumor, ulceration, and inflammatory cell infiltrate) were found to shift during the last decade in the direction of improved prognosis, indicating that tumors are detected earlier than before. The distributions of two other factors (cell type and location of the tumors) shifted in the direction of deteriorated prognosis, suggesting partly that the biologic nature of the disease may have changed and partly that other behavioral factors may have played a role.