The role of misonidazole combined with intraoperative radiation therapy in the treatment of pancreatic carcinoma.

We tested the efficacy of the hypoxic cell sensitizer misonidazole in conjunction with intraoperative electron beam radiation therapy (IORT) and external beam irradiation in patients with locally advanced, nonmetastatic adenocarcinoma of the pancreas. Misonidazole was delivered intravenously (IV) at a dose of 3.5 g/m2 in conjunction with IORT of 1,500 to 2,000 cGy to the pancreas. Additional external beam radiation as administered to 4,960 cGy. The study was based on the premise that the effect of misonidazole would be maximized when a high dose of the drug was administered and, thus, high hypoxic cell sensitization could be obtained when using a high single dose of radiation where the hypoxic fraction would be expected to dominate in the survivors. In a nonrandomized study of 41 patients treated with misonidazole and 22 without, the 1-year local control was 67% and 55%, and 1-year survival was 50% and 77%, respectively. Although there was a bias towards larger tumors in the patients treated with the sensitizer, we were unable to demonstrate an advantage to misonidazole in this clinical situation.