Defining the optimal timing of adjuvant therapy for resected pancreatic adenocarcinoma: A statewide cancer registry analysis

Background: Long-term results of the ESPAC-3 trial suggest that while completing adjuvant therapy (AT) is necessary after resection of pancreatic ductal adenocarcinoma (PDAC), early initiation (within 8 weeks) may not be associated with improved overall survival (OS). The primary aim of this study was to evaluate the OS impact of early versus late AT in a statewide analysis. Methods: Patients with stages I–III PDAC in the Kentucky Cancer Registry (KCR) from 2004 to 2013, were evaluated. Those undergoing pancreatectomy were stratified into two groups (“early,” <8 weeks, vs. “late,” 8–16 weeks). Results: Of 2,221 diagnosed patients with stages I–III, 831 (37.4%) underwent pancreatectomy upfront. Of these, only 420 (50.5%) received AT. Initiation date of AT was not associated with OS (median OS: early, 20.2 vs. late, 19.0 months, P¼0.97). On multivariate analysis, factors that affected OS included stage (II, HR-1.82, P¼0.017; III, HR-3.77, P<0.001), node positivity (HR-1.51, P¼0.004), poorly/undifferentiated grade (HR-1.34; P¼0.011), but not AT initiation date. Conclusions: In this statewide analysis, there was no difference in OS between early and late AT initiation for resected PDAC. The ideal window for AT initiation remains unknown as tumor biology continues to trump regimens from the past decade.