Radical irradiation and misonidazole in the treatment of T2 grade III and T3 bladder cancer.

The results of 2 pilot studies using a new radiation fractionation schedule plus misonidazole (MISO) in the radical radiotherapy of T2 Grade III and T3 carcinoma of the bladder are presented. Forty Gy in 20 daily fractions of 2 Gy was administered to the whole pelvis over 4 weeks followed by 12 Gy in 2 weekly fractions of 6 Gy. These last 2 doses were given after MISO administration. In an initial pilot study (Pilot Study I) MISO was administered orally only. The first two patients received MISO at a dose of 4.5g/m2 orally with each radiation fraction, after which the dose was reduced to 3.0g/m2 because of drug toxicity. In the second pilot study (Pilot Study II) MISO was administered orally at a dose of 3.0g/m2 and intravesically at a dose of 1.0g to 22 patients. The complete response rate at cystoscopy at 6 months in the latter group of patients is 73%, which is significantly better than that of 43% obtained in a retrospective study of historical controls. There have been no late radiation complications in any of the patients nor any MISO toxicity apart from nausea in the patients receiving 3.0g/m2 orally with or without the intravesical MISO.