Objectives: We assessed a conditional probability of survival (CPS) model to determine the probability of living 10 years after ovarian cancer diagnosis after having already survived 5 years.
Methods: We identified patients newly diagnosed with high-grade epithelial ovarian cancer from 1/1/2001-12/31/2009 and treated at our institution. Patients with <3 years follow-up were excluded. CPS was defined as the probability of surviving additional years (y) based on the condition a patient had already survived a given time (x): S(x + y)/S(x). Confidence intervals were estimated using a variation of Greenwood's formula.
Results: Of 916 patients meeting inclusion criteria, 473 (52%) were diagnosed from 2001 to 2005 and 443 (48%) from 2006 to 2009. Median age at diagnosis was 60 years (range, 25-95). The conventional 10-year OS rate for all patients was 29% (95% CI: 26%-32%)-75% (95% CI: 68%-82%) for stage I/II disease, 22% (95% CI: 19%-26%) for stage III, and 6.9% (95% CI: 3.9%-12%) for stage IV. For patients <65 years, the 10-year CPS for 5-year survivors was 65% (95% CI: 59%-70%); for those ≥65 years, it was 48% (95% CI: 38%-57%). For patients <65 years, the 10-year CPS for 5-year survivors by stage was: stage I/II, 89% (95% CI: 81%-94%); stage III, 58% (95% CI: 50%-66%); and stage IV, 26% (95% CI: 12%-42%). For patients ≥65 years, rates by stage were 78% (95% CI: 53%-91%), 42% (95% CI: 30%-53%), and 29% (95% CI: 7%-56%), respectively.
Conclusions: For long-term survivors with high-grade epithelial ovarian cancer, CPS provides better prediction of survival than conventional methods.
Keywords: Conditional probability of survival; Ovarian cancer; Survival outcomes.
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