BackgroundPancreatic cancer is the fourth leading cause of cancer-related death throughout the world. For local advanced and recurrent pancreatic cancer (LAPC/LRPC), chemoradiotherapy (CRT) is a main choice which may prolong their survival and ease patients’ symptoms.MethodsWe constructed a database of 65 patients with LAPC/LRPC treated from June, 2004 to February, 2018. We used log-rank test to evaluate the different overall survival (OS) rates of all factors involved, and used cox regression model to find out independent prognostic factors for these patients.ResultsThe median OS time for 65 eligible patients was 23.6 months. 47 (72.3%) and 18 (27.7%) patients had unresectable LAPC and LRPC, and median OS time was 17.2 and 40.7 months (P= 0.02), respectively. The mean biological effective dose (BED) to gross tumor volume (GTV) was 64.8Gy (46.7-85.5 Gy). 11(16.9%) and 54(83.1%) patients had BED> 72 Gy and BED≤ 72 Gy, and their mOS was 31.8 and 21.9 months (P= 0.08), respectively. Simultaneous dose boost to interval GTV (GTVin) was applied to 23 patients (35.4%). Patients with large GTV volume (≥ 109.2 cm3) may benefit from radiation dose boost (mOS: 27.6 vs. 5.3 months, P= 0.004). Patients with symptom relief including relief of pain, jaundice, and/or diarrhea had higher OS rates than those without response (mOS: 25.7 vs. 13.2 months, P< 0.01) and multivariate cox regression analysis suggested symptom relief was the most significant prognostic factor for OS (HR= 0.44, 95%CI 0.35-2.36, P= 0.02).ConclusionCRT with simultaneous integrated boost of radiation dose may bring survival benefit for LAPC/LRPC patients with bulk tumor. Symptom relief is the most significant prognostic factor for LAPC/LRPC patients after comprehensive CRT.