The trajectory of conditional, recurrence-free, and long-term survival in a complete 10-year cohort of patients with advanced ovarian cancer

Background: The prognosis in advanced ovarian cancer is generally poor since the majority experience recurrence. Nevertheless, there is a chance of cure and very long-term survival may be achieved. However, traditional survival metrics do not account for the dynamic changes in prognosis over time. Our objectives were to examine conditional, very long-term and recurrence-free survival, in addition risk-factors for recurrence. Methods: In this observational study, all patients diagnosed with advanced ovarian cancer between 2009 and 2018 in the Stockholm/Gotland region, Sweden, were identified in the Swedish Quality Registry of Gynecologic Cancer. Conditional and recurrence-free survival were estimated with the Kaplan Meier method. The association between predefined clinical factors and hazard of death was analysed with Cox regression yielding hazard ratio (HR) with 95% confidence interval (CI). Results: A total of 888 patients were analysed of which 87.0% (n = 740) experienced a recurrence and 8.5 % (n = 76) were alive > 10 years. The 5-year conditional survival increased from 33.0% (95% CI: 30-36) in patients who had survived 1 year to 57.0% (95% CI: 50-63) in patients who had already survived 5 years. The median recurrence-free survival was 18 months (95% CI: 16-19). Risk factors associated with recurrence included any residual tumour (> 10 mm; HR: 2.15; 95% CI: 1.65 to 2.80) and evidence of disease at end of first line treatment (HR: 2.40; 95% CI: 1.97 to 2.93; p < 0.001). Interpretation: Conditional survival improves significantly with time survived following an advanced ovarian cancer diagnosis. Most patients experience relapse within 1 year after completing first-line treatment, nevertheless long-term survival is possible.