Prognosis and conditional survival among women with newly diagnosed ovarian cancer

Using a longitudinal dataset from US oncology centers, this study included 6778 women with ovarian cancer. We calculated CS rates as the Kaplan-Meier probability of surviving an additional 1 or 5 years, given no mortality (OS) or disease progression (rwPFS) event in the previous 0.5–5 years since first-line chemotherapy initiation, adjusted for factors associated with OS based on multivariable Cox regression.

Median study follow-up was 9 years (range, 1–44) from first-line initiation to data cutoff (17-Feb-2021). Median OS was 58.0 months (95% CI, 54.9–60.8); median rwPFS was 18.4 months (17.4–19.4). The adjusted 1-year CS rate (ie, rate of 1 year additional survival) did not vary based on time alive, whereas the adjusted 5-year CS rate increased from 48.5% (47.0%–50.1%) for women who had already survived 6 months to 66.4% (63.3%–69.6%) for those already surviving 5 years (thus surviving 10 years total). The adjusted 1-year CS rate increased from 90.4% (89.5%–91.4%) with no rwPFS event at 6 months to 97.6% (96.4%–98.8%) with no rwPFS event at 5 years; adjusted 5-year CS rate increased from 53.7% (52.0%–55.5%) to 85.0% (81.2%–88.9%), respectively.

This analysis extends the concept of CS by also conditioning on time progression-free. Patients with longer rwPFS experience longer survival than patients with shorter rwPFS.