Correlation between progression-free survival and overall survival in patients with ovarian cancer after cytoreductive surgery: a systematic literature review

OBJECTIVES: This analysis aimed to better define the relationship between progression-free survival and overall survival in adult patients with ovarian cancer (including fallopian tube or primary peritoneal cancer) following primary cytoreductive surgery or interval cytoreductive surgery. METHODS: A systematic literature review was carried out across the Medline, Embase, and Cochrane Central databases on 7 July 2020 (date limits 1 January 2011 to 7 July 2020) to identify studies with the following eligibility criteria: clinical trials/observational studies including >200 patients with ovarian cancer aged ≥18 years, evaluating overall survival/progression-free survival following cytoreductive surgery by residual disease status in the United States, Europe, Japan, or China. Weighted linear regression models were used to assess any correlation between median progression-free survival and overall survival, and between logHR for progression-free survival and logHR for overall survival. Risk of bias was assessed for all included studies. RESULTS: Of the 50 studies reported, 43 were observational studies (41 retrospective and two prospective cohort studies), and seven were reporting for randomized clinical trials—of which four were retrospective data analyses. For analyses of the relationship between overall survival and progression-free survival, 21 studies were eligible. The weighted linear regression model showed a strong positive association between the two survival endpoints. Goodness-of-fit analysis measured the adjusted R(2) as 0.84 (p<0.001); a positive association was also observed between logHRs for overall survival and progression-free survival in the included studies. CONCLUSIONS: Median progression-free survival was predictive of median overall survival. This correlation between progression-free survival and overall survival after primary treatment for ovarian cancer highlights the validity of progression-free survival as a primary endpoint. Observational studies contributed most data, with limited information on disease stage and histology.