Phase II trial of S-1 and concurrent radiotherapy in patients with locally advanced pancreatic cancer

Abstract

S-1 has a favorable effect in unresectable pancreatic cancer and a potential radiosensitizer. In addition, daily oral administration of S-1 is more convenient than continuous infusion of 5-fluorouracil. This study was designed to evaluate the efficacy and safety of S-1 and concurrent radiotherapy in patients with locally advanced pancreatic cancer. Eligibility criteria were histologically proven pancreatic adenocarcinoma, locally advanced disease, and no previous treatment. S-1 was administered orally at a dose of 40 mg/m(2) twice daily from day 1 to 14 and from day 22 to 35, and concurrent radiotherapy (a total dose of 50.4 Gy) was delivered in 28 fractions. One month after treatment completion, tumor response was evaluated by computed tomography (CT). A total of 25 patients were evaluable for efficacy and toxicity on the basis of the intention-to-treat analysis. The response rate and disease control rate were 24.0 and 68.0%, respectively. There was no treatment-related death or grade 4 toxicity. The most common grade 3 hematologic and non-hematologic toxicities were thrombocytopenia (4.0%) and anorexia (20%), respectively. All toxicities were tolerable and transient. The median time-to-progression and median overall survival were 6.5 months (95% confidence interval, 4.1-9.0 months) and 12.9 months (95% confidence interval, 6.7-19.0 months), respectively, and the 1-year survival rate was estimated to be 43%. S-1 and concurrent radiotherapy shows favorable efficacy for disease control against locally advanced pancreatic cancer and was well tolerated with no severe toxicities.