Impact of renal function on the efficacy and safety of S-1 with concurrent radiotherapy for locally advanced pancreatic cancer.

301Background: S-1 is an oral agent consisting of a mixture of tegafur which is a prodrug of 5-fluorouracil (5-FU), 5-chloro-2,4-dihydroxypyrimidine (DHP) and potassium oxonate. Serum concentration of 5-FU increases in case of renal dysfunction due to decrease of DHP excretion into urine. The aim of this study was to evaluate the influence of renal function to the efficacy and safety of S-1 with concurrent radiotherapy (RT) for locally advanced pancreatic cancer (LAPC). Methods: This study was an integrated exploratory analysis of JCOG1106 and LAPC- S1RT, in which pts with LAPC received RT (50.4Gy/28 fr over 5.5 weeks) and concurrent S-1 (40 mg/m2/dose, bid. on the day of irradiation). Eligibility criteria for this study were pts who received both irradiation and S-1 at least once without induction chemotherapy, and who had creatinine clearance (CCr) ≥ 50 ml/min at the time of registration. We assigned pts into high (≥ 80 ml/min) and low (< 80 ml/min) CCr groups. The primary endpoint was the incidence of ...