BACKGROUND: The feasibility and efficacy of high dose conformal radiotherapy were examined in the treatment of patients with locally advanced, unresectable pancreatic carcinoma. METHODS: Forty-four patients with pathologically confirmed, unresectable pancreatic adenocarcinoma without distant metastases were treated in a Phase II study. The patients received three-dimensional, planned, high dose conformal radiotherapy (70-72 grays). Toxicity was scored according to the World Health Organization criteria. Follow-up time ranged from 7 months to 25 months (median, 9 months). RESULTS: The treatment was feasible. Forty-one patients received the intended total dose. Treatment was never stopped because of toxicity. Acute toxicity was mainly Grade 1 and Grade 2 (in 70% and 57% of patients, respectively), whereas Grade 3 toxicity was seen in 9% of patients. One fatal event occurred that was not treatment related. Late Grade 3 and Grade 4 gastrointestinal toxicity was seen in 3 patients and 2 patients, respectively. Late (Grade 5) gastrointestinal bleeding was observed in 3 patients, 2 of whom had local tumor progression. At 3 months, reduction in tumor size was seen in 27% of patients, stable disease was seen in 20% of patients, and local disease progression was seen in 40% of patients. Ultimately, local disease progression was observed in 44% of patients. No true partial or complete responses were documented. The median survival from the time of diagnosis was 11 months (10 months from the start of radiotherapy). Seventeen of 25 patients (68%) experienced pain relief. CONCLUSIONS: High dose conformal radiotherapy for the treatment of patients with locally advanced pancreatic carcinoma is feasible with acceptable toxicity. In case of pain, it can offer palliation. The efficacy of the treatment in terms of prolongation of life is not proven. Distant metastases remain the major proble