Post-progression survival (PPS) and improvements in progression-free survival (PFS) in randomized controlled trials (RCTs) in advanced gastric cancer (AGC).

Abstract

93 Background: Since PPS may influence overall survival (OS), studying PPS may help in understanding why gains in PFS do not always translate into gains in OS. Methods: We searched PubMed for RCTs on first-line therapy for AGC published between 01/82 and 01/12. We estimated mean PFS and OS (in months) using the area under the published Kaplan-Meier curves, computing mean PPS as mean OS minus mean PFS for each trial arm. We compared PPS between trial arms grouped according to PFS duration (longer versus shorter PFS, regardless of statistical significance) and world region (using t tests). Results: We retrieved 53 trials (25 were phase III, 24 were randomized phase II, and 4 had no explicit phase) enrolling 12,050 patients in 121 arms. We could estimate mean endpoints for 33 trials (26/6/1 with 2/3/4 arms), which were more likely to be phase III than the 20 trials with no Kaplan-Meier curves for both endpoints. The average mean PPS was almost identical between trial arms with longer or shorter PFS. Use of PPS assessed as median OS minus median PFS yielded qualitatively similar results. Conclusions: Treatments that improve PFS do not seem to influence PPS. Asian trials appear to have longer OS due to longer PPS, not PFS. Work with individual patient data collected worldwide by the GASTRIC group is under way to confirm our findings. [Table: see text]