Utilization and Comparison of Restricted Mean Survival and Piecewise Cox Model: Analyzing the Effect of Neoadjuvant Chemotherapy in Patients with Resectable Pancreatic Cancer

• Activity Number: 291 - Contributed Poster Presentations: Biometrics Section
• Type: Contributed
• Date/Time: Tuesday, August 9, 2022 : 10:30 AM to 12:20 PM
• Sponsor: Biometrics Section
• Author(s): Pingfu Fu* and Shufen Cao and Fang Liu and David Bajor and Yufei Li
• Companies: Case Western Reserve University and Case Western Reserve University and Case Western Reserve University and Case Western Reserve University and Case Western Reserve University
• Keywords: RMST; Piece-wise Cox model; overall survival; neoadjuvant chemotherapy ; resectable pancreatic cancer; clinical trial

Abstract

Upfront surgery (UFS) followed by adjuvant treatment is considered as a standard treatment for resectable pancreatic cancer (RPC). The effects of neoadjuvant chemotherapy followed by surgery (NAC) compared to UFS still under debate due to lack of enough evidence. We aimed to compare the overall survival (OS) of RPC patients receiving NAC and UFS treatment based on chart review of 181 patients with RPC (131 with UFS and 50 w NAC) were reviewed. We utilized Kaplan-Meier (KM), restricted mean survival time (RMST), and piecewise Cox model due to violation of PH assumption to analyze the effect of treatment on OS. KM indicated a significant difference in OS between NAC and UFS with Wilcoxon test, but not Log-rank test. Non-parametric RMST and RMST regression suggested no difference of OS between NAC and UFS. However, piecewise Cox model indicates a significant improvement in OS for patients receiving NAC over UFS up to 18.8 months. In conclusion, the RMST provides a clinically meaningful and easily interpretable measure for clinical studies with survival data. Piece-wise Cox model, however, provides a useful and sensitive tool for assessing treatment effect over different time frames.