Background: A hypothesis generated a retrospective analysis of the improvement of survival over time in patients with cutaneous melanoma (CM) in order to identify factors contributing to this progress.
Methods: A cohort of 4791 patients diagnosed with primary CM in southern Germany between 1976 and 2001 was analyzed. Kaplan-Meier analyses were performed to estimate and to compare overall survival (OS) and survival after first recurrence (SAR). The Cox proportional hazards model was used to evaluate the effect of multiple variables on OS and SAR.
Results: Diagnosis of primary CM during 1990-2001 compared with 1976-1989 was associated with more favorable 10-year OS (88.6% vs 80.0%, P < .0001). The median tumor thickness at primary diagnosis was significantly lower during the second period (0.75 mm vs 1.07 mm, P < .0001). In the multivariate analysis, adjusted for tumor thickness, ulceration, age, gender, and anatomical site, the period of diagnosis retained its significance as a predictor of OS (P = .002). The SAR was more favorable during the second period in patients who developed their first metastasis in the regional lymph nodes (45.2% vs 32.9%, P = .017) or in distant sites (13.4% vs 2.0%, P = .0002) and this finding persisted in the multivariate analysis.
Conclusions: Improvement of survival of CM patients diagnosed 1990-2001 as compared with 1976-1989 may not be entirely attributable to factors associated with early diagnosis and more favorable primary tumors. Therefore, factors of melanoma management, which changed between the 2 time periods, such as sentinel node biopsy, adjuvant treatment, structured follow-up, and surgical interventions in distant metastasis, may have to be taken into account.