Impact of neoadjuvant radiation on survival in patients with pancreatic cancer undergoing neoadjuvant chemotherapy followed by pancreatectomy.

453Background: Pancreatic adenocarcinoma (PDAC) carries a dismal prognosis. Neoadjuvant chemoradiation therapy (NACR) has been introduced to enhance the outcomes of patients with borderline resectable and locally advanced PDAC, however the role of radiation therapy remains largely unknown. Methods: The National Cancer Database (NCDB) was queried for patients with stage I-III PDAC who underwent surgical resection from 2004 to 2014. Patients undergoing NACR were compared to those undergoing neoadjuvant chemotherapy (NAC) alone. The association between clinical characteristics and overall survival (OS) was assessed using the Kaplan-Meier method and multivariable Cox regression model. Results: Of 3,133 patients, 2,351 (75%) patients underwent NACR and 782 (25%), NAC alone. Most patients were Caucasians (84%), treated at academic institutions (67%) and underwent pancreaticoduodenectomy(74%). Median follow-uptime was 32 months (IQR, 22-50 months). Median number of lymph nodes examined (LNE) and number of posi...