Adjuvant therapy for pancreatic body or tail adenocarcinoma: a study of the National Cancer Database

BACKGROUND: The optimal multimodality therapy for pancreatic ductal adenocarcinoma in the body or tail of the pancreas (PDAC-BT) is unclear. The purpose of this study was to compare overall 5-year survival between patients treated with adjuvant chemotherapy, adjuvant chemoradiation, and surgery alone. METHODS: Patients from the National Cancer Database (1998–2012) with resected stage I or II PDAC-BT were included. Overall survival between the three treatment groups was compared using Cox proportional-hazards regression, propensity-score matching, and the Kaplan–Meier method. RESULTS: Of the 700 patients included in the analysis, 189 (27%) were treated with chemotherapy, 226 (32%) were treated with chemoradiation, and 285 (41%) were treated with surgery alone. Chemoradiation was associated with higher survival than surgery alone [adjusted hazard ratio (HR(adj)): 0.67; 95% confidence interval (CI): 0.54, 0.84; p = 0.001], but there was no difference between chemotherapy and chemoradiation (HR(adj): 0.82; 95% CI: 0.65, 1.05; p = 0.115). In propensity-score matched cohorts, median survival was 24.1 months (95% CI: 20.4, 28.4) with chemotherapy and 25.4 months (95% CI: 22.1, 31.7) with chemoradiation (log-rank p = 0.122). Among patients with positive resection margins, chemoradiation was associated with higher survival compared with chemotherapy (HR(adj): 0.54; 95% CI: 0.32, 0.92; p = 0.022). In this subgroup of the propensity-score matched cohorts, median survival was 9.5 months (95% CI: 8.4, 16.0) with chemotherapy and 18.3 months (95% CI: 11.6, 26.3) with chemoradiation (log-rank p = 0.011). CONCLUSION: In patients with resected pancreatic body or tail adenocarcinoma, adjuvant chemoradiation was associated with higher survival compared with surgery alone. Among patients with positive resection margins, adjuvant chemoradiation was associated with higher survival compared with adjuvant chemotherapy.