Real-world Conditional Survival Analysis of Women With Newly Diagnosed Ovarian Cancer

ASCO Annual Meeting 2020 Presentation
Authors Elizabeth A. Szamreta, Matthew J. Monberg, Kaushal Desai, Xin Chen, Megan Othus

Background: A critical question in determining long-term prognosis for women with newly diagnosed ovarian cancer (OC) is whether or not their risk of death changes with time. The emergence of large, well-populated real-world datasets permits assessment of conditional survival (CS) given prior overall survival (OS) or progression-free survival (PFS).

Methods: The Tempus EMR clinical dataset consists of patients from both National Cancer Institute designated centers and a sample of community oncology centers in the U.S. This study included adult women with a primary diagnosis of ovarian, fallopian tube, or peritoneal cancer from 1982 to 2018; women treated with a poly-ADP ribose polymerase (PARP) inhibitor were excluded due to low numbers & limited follow-up (final n = 2,031). The effects of patient attributes on OS were estimated using Cox regression. We calculated CS as the Kaplan-Meier probability of surviving an additional y years (from first line chemotherapy initiation), given no OS or PFS event in the previous x (<y) years.

Results: Median age was 61 years and 68% of patients were Caucasian. The majority (92%) had epithelial histology, 58% were stage 3 or 4, and 49% were ECOG 0 or 1. Median OS was 37 months (95% CI: 36-39), and OS differed by age, stage, and performance status; adjusted hazard ratios (HRs) for OS were 1.3 (95% CI: 1.0, 1.5) for age > 65 versus < 45, 2.4 for stage 4 versus stage 1 (95% CI: 1.7, 3.4), and 1.4 for ECOG 2 to 4 versus 0 or 1 (95% CI: 1.2, 1.7). Conditional 1- or 5-year survival rate did not vary based on prior OS. However, CS rates among women alive without disease progression increased with time: 1-year and 5-year survival rates (with 95% CI) were 86% (84-87) and 28% (26-31), respectively, in women alive without progression at 6 months, but increased to 94% (89-97) and 53% (44-62) in women alive without progression at 3 years.

Conclusions: Long-term prognosis, as shown by conditional survival rates, did not improve based on time alive since initiation of chemotherapy. However, women with longer time without disease progression had lower rates of death and a better prognosis.