Clinical outcomes of pancreatic ductal adenocarcinoma resection following neoadjuvant chemoradiation therapy vs. chemotherapy.

PURPOSE: We compared the clinical outcomes of pancreatic ductal adenocarcinoma (PDAC) resection after neoadjuvant chemoradiation therapy (NACRT) vs. chemotherapy (NAC). METHODS: The study population comprised 81 patients with UICC stage T3/4 PDAC, treated initially by NACRT with S-1 in 40 and by NAC with gemcitabine + S-1 in 41. This was followed by pancreatectomy with routine nerve plexus resection in 35 of the patients who had received NACRT and 32 of those who had received NAC. We compared the survival curves and clinical outcomes of these two groups. RESULTS: The rates of clinical response, surgical resectability, and margin-negative resection were similar. The NACRT group patients had significantly higher rates of Evans stage ≥IIB tumors (29 vs. 0 %, respectively, p = 0.010) and negative lymph nodes (49 vs. 16 %, respectively, p = 0.021) than the NAC group patients. There was no difference in disease-free survival between the groups, but the disease-specific survival of the NAC group patients was better than that of the NACRT group patients (p = 0.034). Patients undergoing pancreatectomy with nerve plexus resection following NACRT had significantly higher rates of intractable diarrhea and ascites but consequently received significantly less adjuvant chemotherapy and therapeutic chemotherapy for relapse. CONCLUSION: NACRT followed by pancreatectomy with nerve plexus resection is superior for achieving local control, but postoperative diarrhea and ascites may prohibit continuation of adjuvant chemotherapy or chemotherapy for relapse (UMIN4148).