Ten-year conditional probability of survival for patients with ovarian cancer: A new metric tailored to Long-term survivors

Abstract

ObjectivesWe 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. MethodsWe 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. ResultsOf 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. ConclusionsFor long-term survivors with high-grade epithelial ovarian cancer, CPS provides better prediction of survival than conventional methods.