Neoadjuvant chemotherapy with gemcitabine and S-1 for resectable and borderline pancreatic ductal adenocarcinoma: A prospective, multi-institutional, phase II trial

283 Background: Although surgical resection is the only curative treatment for pancreatic ductal adenocarcinoma (PDAC), recurrence rates are very high even if complete resection is performed. Accordingly, a new therapeutic strategy against PDAC is needed. Combination with gemcitabine and S-1 (GS) as first line chemotherapy is promising. The purpose of this study is to evaluate the feasibility and efficacy of GS for resectable and borderline PDAC in the neoadjuvant chemotherapy (NAC). Methods: This study is a prospective, multi-institutional, single-arm, phase II trial. Neoadjuvant chemotherapy with gemcitabine and S-1(NAC-GS) for resectable and borderline PDAC was performed as follows. Gemcitabine was given at a dose of 1,000 mg/m2 on days 1 and 8 of each cycle. S-1 was administered orally at a dose of 40 mg/m2 twice daily for the first 14 consecutive days followed by a 7-day rest. Each cycle was repeated every 21 days. The primary endpoint was the 2-year survival rate. Secondary endpoints were feasibility, resection rate, pathological effect, recurrence-free survival and tumor marker status. Results: 36 patients were enrolled between 2008 and 2010. 35 were eligible for participation in this trial. The most common toxicity was neutropenia in response to 90% of the relative dose intensity. Radiological tumor shrinkage and decreases of CA19-9 levels were seen in 69% and 89%, respectively. R0 resection rate was 87%, and the morbidity rate (40%) was acceptable. The 2-year survival rate of the total cohort was 45.7%. Patients undergoing surgical resection without distant metastases after NAC-GS (n=27) showed an increased median overall survival (34.7 months), compared with 10.0 months for resection with distant metastases or non-resection (p=0.0017). Conclusions: NAC-GS is safe and well tolerated in a multi-institutional setting. NAC-GS is encouraging patients with resectable and borderline PDAC because of better outcomes. Clinical trial information: UMIN-000001504.