Development of prognostic factors and survival in cutaneous melanoma over 25 years

BACKGROUND: Recent studies revealed that incidence rates of cutaneous melanoma (CM) were leveling off predominantly among younger people and patterns suggested birth-cohort effects. The current study analyzed the development of prognostic factors and survival in incident CM over 25 years. METHODS: All 45,483 patients with incident CM diagnosed between 1976 and 2000 recorded by the German Central Malignant Melanoma Registry were considered. Linear and logistic regression analyses were used to judge time trends. Trends of survival rates were tested with the multivariate Cox model. RESULTS: Median tumor thickness decreased from 1.81 mm in 1976 to 0.53 mm in 2000 (P < 0.0001). The percentages of in situ and level II CM increased, respectively (P < 0.0001). The percentage of ulcerated CM decreased (P < 0.0001). The percentage of superficial spreading melanoma increased, whereas the percentage of nodular melanoma decreased (P < 0.0001). These time trends were all significant in the strata of gender, however, male patients presented in general with more advanced disease. Between 1976 and 2000, the average patient got older (P < 0.0001). The percentage of patients diagnosed with the primary tumor alone increased (P < 0.0001). Across the 25 years of observation, adjusted survival rates did not increase for females (P = 0.1561) but they increased for males (P < 0.0001). CONCLUSIONS: The data demonstrated a strong trend towards prognostically more favorable CM most likely due to earlier diagnosis. Men and older people should be the focus of health promotion activities as they presented with more advanced disease.