Conditional survival in advanced-stage epithelial ovarian cancer: Implications for survivorship planning and patient counseling.

Abstract

e17500 Background: Advanced-stage epithelial ovarian cancer (EOC) is characterized by biological heterogeneity and poor outcomes. Traditional survival statistics fail to capture the dynamic, time-dependent nature of prognosis. Conditional survival provides a framework for updating prognosis over time and offers clinically meaningful information for patient counseling and survivorship planning. In this two-decade real-world study, we applied conditional survival analysis to evaluate how prognosis evolves as patients live longer and remain progression-free. Methods: We retrospectively analyzed patients with FIGO stage III–IV epithelial ovarian cancer who underwent primary or interval cytoreductive surgery between 2004 and 2024. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. Conditional overall survival (CS-OS) and conditional progression-free survival (CS-PFS) were calculated for additional 1- and 5-year intervals among patients who had survived or remained progression-free for 6 months, 1 year, 3 years, or 5 years after surgery. Results: A total of 808 patients with FIGO stage III–IV epithelial ovarian cancer were included. Median OS and PFS were 4.37 and 1.70 years, respectively, and approximately 11% survived beyond 10 years. Peritoneal dissemination and platinum resistance were independent predictors of poor survival. Conditional survival improved with increasing time survived. The 1-year CS-OS increased from 87% at 6 months to 95% at 5 years, while the 5-year CS-OS rose from 49% to 66%. Similarly, the 1-year CS-PFS increased from 89% to 95%, and the 5-year CS-PFS improved from 44% to 62%. In stage-stratified analyses, 5-year CS-OS increased from 43% to 58% in FIGO stage III disease and from 26% to 44% in FIGO stage IV disease. Conclusions: Conditional survival analysis provides time-updated prognostic information that complements traditional survival estimates and more accurately reflects long-term outcomes. Incorporating conditional survival into clinical practice may support more individualized patient counseling and inform survivorship planning, particularly for patients who remain alive and progression-free beyond the initial high-risk period. Conditional survival rates based on previous time survived (CS-OS) or on time without progression (CS-PFS) in patients with advanced epithelial ovarian cancer. Time already survived/progression-free CS-OS at 1 year (95% CI) CS-OS at 5 years (95% CI) CS-PFS at 1 year (95% CI) CS-PFS at 5 years (95% CI) 6 months 87 (84–90) 49 (45–53) 89 (86–92) 44 (40–48) 1 year 88 (85–91) 49 (45–53) 90 (87–93) 46 (42–50) 3 years 91 (88–94) 57 (52–62) 93 (89–96) 54 (50–58) 5 years 95 (92–98) 66 (61–71) 95 (91–98) 62 (57–67)