Phase II study of conventional fractionated radiotherapy versus hyper-fractionated accelerated radiotherapy concomitant with low dose gemcitabine for patients with pancreatic cancer

Abstract

14017 Background: Concurrent radiotherapy and chemotherapy with gemcitabine (GEM) has been reported to improve the median survival of patients with unresectable pancreatic cancer. Although hyperfractionated accelerated radiotherapy (HART) was administered to pancreatic cancer recently, the efficacy is unclear. Phase II study was conducted to evaluate the efficacy and the toxicity of HART concomitant with twice-weekly low dose GEM compared with conventionally fractionated radiotherapy (CRT) for unresectable pancreatic cancer. Methods: Between April 2001 and April 2004, 34 untreated eligible patients with histologically proven unresectable pancreatic cancer were enrolled. In CRT group (n=15), 50.4Gy was delivered in 28 fractions of 1.8Gy/day. In HART group (n=19), 50Gy was delivered in 40 fractions of 1.25Gy twice a day. All patients were treated with conformal radiation using 5mm multileaf collimeter. Concurrent chemotherapy with GEM (40mg/m2) was administered twice a week to both groups. Chemotherapy was suspended for Grade 3 toxicities or increase in temperature more than 38 °C. Response evaluations were conducted at six weeks after the treatment. Maintenance chemotherapy composed of GEM (1000mg/m2/week) for 3weeks was repeated every 4 weeks thereafter. Results: The median survival time (MST) was 11.3 months in CRT group and 12.9 months in HART group. The 1- and 2-year survival rates were 42.9% and 28.6% in CRT group, 52.9% and 17.6% in HART group. There was no significant difference in response rate between CRT and HART group (35.7% vs. HART; 35.3%). The median time to progression (TTP) was significantly prolonged in HART group (9.7months) compared with CRT group (5.9 months) (p=0.02). Overall treatment time was significantly shorter in HART group (37days) than CRT group (45days) (p=0.002). There was no significant deference in toxicity between CRT and HART group. Conclusions: HART concomitant with low dose GEM was well tolerated with acceptable toxicity and prolonged median TTP and MST with shortening of treatment time compared with conventional radio-chemotherapy. This regimen appears to be one of the crucial therapies for patients with unresectable pancreatic cancer. No significant financial relationships to disclose.