Cassia B. Trewin-Nybråten

Ovarian cancer survival in Germany: a nationwide analysis by stage and histotype

Previous population-based studies on ovarian cancer survival have evaluated less granular disease staging categories and histologic sub-types than are in current use, and there is a need to assess survival in the context of more contemporary treatment practices and histotype classifications. Using flexible parametric models, we assessed the 1-, 3-, 5-, and 10-year net survival and excess mortality hazards of 54,267 incident invasive ovarian cancer cases by stage and histology and 9478 borderline cases diagnosed between January 1, 2010 and December 31, 2021 recorded in Germany. Net survival differed markedly by stage, with consistently favorable long-term survival for early-stage (I to II) and poor outcomes for advanced-stage (III to IV) disease across histotypes. Although most stage I tumors showed high 10-year net survival (≥ 77%), carcinosarcomas represented a notable exception. Net survival declined with advancing stage, with 10-year estimates ranging from 46% to 76% for stage II, 18% to 55% for stage III, and poor 5-year survival for stage IV tumors (15% to 41%). Considering patterns by time since diagnosis, the excess mortality hazard was the highest across all histotype-stage groups during the first 3 years with variability suggestive of histotype-specific treatment resistance and disease recurrence. The influence of stage decreased over the follow-up, with the largest impact mostly observed during the first year after diagnosis. Net survival for borderline tumors was high (10-year survival = 92.9%). Net survival was favorable for patients with early-stage disease. Variability was observed across histotypes by stage. The early post-diagnosis period is a critical window for excess mortality, and the development of histotype-specific treatments is needed.