A Phase II Study of Short-Course Neoadjuvant Chemoradiotherapy with Gemcitabine, S-1, and Hypofractionated Radiotherapy for Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma.

Neoadjuvant chemoradiotherapy (NACRT) is increasingly used for pancreatic ductal adenocarcinoma (PDAC), yet the optimal regimen remains unclear. This phase II trial evaluated the feasibility and efficacy of a short-course NACRT regimen comprising gemcitabine, S-1, and hypofractionated radiotherapy in patients with resectable (R) or borderline resectable (BR) PDAC. Patients received NACRT with gemcitabine (1000 mg/m2 on days 1 and 8), oral S-1 (60 mg/m2/day for 14 days), and hypofractionated radiotherapy (30 Gy in 10 fractions over 2 weeks). The primary endpoint was the R0 resection rate. Secondary endpoints included treatment completion, adverse events, tumor response, and survival. In total, 54 patients were enrolled. Treatment completion ranged from 87 to 98