Purpose: Maximal therapeutic gain in xenograft sarcoma and toxicity for jejunal mucosa is time dependent for concurrent gemcitabine and radiotherapy (RT). We used a time-dependent schedule to determine the maximal-tolerated dose and dose-limiting toxicities (DLTs; Grade 4 hematologic or Grade 3 other toxicity).
Methods and materials: Patients with pancreatic cancer (n = 33), periampullary carcinoma (n = 1), or bile duct cancer (n = 2) were treated with 3-day conformal RT with 50.4 Gy (tumor, lymphatics) plus a 5.4-Gy boost. Concurrent cisplatin (20 mg/m(2)/d on Days 1-5 and 29-33) and gemcitabine (initially 600 mg/m(2), weekly on Fridays 68 h before RT) were administered. Because of DLT, the doses were reduced to 500 mg/m(2) weekly and then 500, 400, or 300 mg/m(2) on Days 2, 5, 26, 33.
Results: DLT occurred at all dose levels of gemcitabine >300 mg/m(2). Fourteen patients were treated at the recommended Phase II dose of gemcitabine (300 mg/m(2)) without DLT. The response to chemoradiation allowed 10 of 30 initially unresectable patients with primary pancreatic carcinoma to undergo radical surgery, including a complete response in 2 cases.
Conclusions: At the recommended Phase II dose, chemoradiation with gemcitabine and cisplatin can be administered safely in pancreatic carcinoma. However, at higher dose levels, toxicity is severe and frequent. Patients with a chance for conversion to resection could benefit from this schedule.