Predictors of neoadjuvant chemotherapy efficacy in localized pancreatic head cancer: A 15-year experience at a high volume pancreatic cancer center.

Abstract

e15724 Background: Surgery followed by adjuvant chemotherapy (SF) is the standard approach for localized pancreatic adenocarcinoma (PC). Although neoadjuvant chemotherapy (NC) is being increasingly used, its efficacy remains debatable. This study aims to identify baseline factors associated with benefit from NC as compared to SF for PC. Methods: Review of a prospectively maintained database of resected localized head PC undergoing NC or SF at a tertiary referral hospital from 2002 to 2018. Baseline factors investigated included clinical stage by EUS (7th edition AJCC), CT vessel involvement, and serum CA19-9. Baseline CA19-9 levels were grouped into mild (37-200), moderate (200-900), and marked elevations (≥ 900). Patients with baseline serum CA19-9 < 37 IU/dL were excluded from the analysis. Results: In total, 269 patients were evaluated: 165 (61%) received NC and 104 (39%) had SF. Mean patient age was 68.3 years and 50% were females. Of these, 42% had stage IIB, 44% had N1 disease, and 38% had vascular involvement. Compared to SF approach, NC was associated with improved median survival for CA19-9 of < 200 IU/dL (30 vs 21 months, p = 0.08), 200-900 IU/dL (32 vs 17 months, p < 0.01), and the ≥900 IU/dL (33 vs 12 months, p < 0.01) groups. On Cox regression, NC was the only baseline factor predictive of improved survival in the groups with moderate (HR:0.35,[95% CI:0.20-0.62];p < 0.01) and marked (HR:0.36,[95% CI:0.18-0.71];p < 0.01) pretreatment CA19-9 elevation. Notably, NC was not predictive of improved survival in the cohort with mild CA19-9 elevation. Conclusions: This study identifies a cohort of patients that benefits from neoadjuvant chemotherapy over a surgery first approach for localized pancreatic head cancer. Elevation in baseline CA19-9 may serve as the strongest indicator for chemotherapy before resection.