Assessing the correlation between second progression-free survival (PFS2) and overall survival (OS) in advanced prostate cancer patients using medical data vision (MDV) claims database in Japan

Objective To assess the correlation between PFS2 and OS among patients with advanced prostate cancer (PC) in a real-world setting for Japan. Methods This was a retrospective analysis using the Japanese MDV database. Patients with nmCRPC (non-metastatic Castration-Resistant PC), mCRPC (metastatic Castration-Resistant PC), and mCNPC (metastatic Castration-Naive PC) were identified and their medical records were investigated for PFS2 and death. Association between PFS2 and OS was determined using the Pearson's, Spearman's, Kendall's Tau, and Fleischers' correlation coefficients. Results A total of 386,484 patients with PC were identified from the database, of which, 1,783 patients with nmCRPC, 630 with mCRPC, and 454 with mCNPC met the predefined eligibility criteria. Significant correlation between PFS2 and OS was observed in patients with nmCRPC (Pearson's r = 0.873; 95% CI: 0.849-0.897, Spearman's r = 0.909; 95% CI: 0.893-0.925; Kendall's Tau r = 0.831; 95% CI: 0.812-0.850, Fleischers' r = 0.682; 95% CI: 0.601-0.764), mCRPC (Pearson's r = 0.812; 95% CI: 0.758-0.865, Spearman's r = 0.895; 95% CI: 0.868-0.923, Kendall's Tau r = 0.789; 95% CI: 0.755-0.823, Fleischers' r= 0.439; 95% CI: 0.334-0.544), and mCNPC (Pearson's r = 0.931; 95% CI: 0.899-0.964, Spearman's r = 0.943; 95% CI: 0.922-0.964, Kendall's Tau r = 0.866; 95% CI: 0.836-0.896, Fleischers' r = 0.756; 95% CI: 0.624-0.888). Conclusions The results of this study indicate a significant correlation between PFS2 and OS, which adds additional evidence to the existing literature of using PFS2 as a surrogate endpoint for OS in patients with PC.