Results of a randomised study to evaluate influence of dose on morbidity in radiotherapy for bladder cancer.

Ninety-four patients with invasive transitional-cell carcinoma of the bladder were randomised to receive three different doses of megavoltage X-rays. Doses of 50.0 Gy, 52.5 Gy and 57.5 Gy were given in 20 daily fractions. Patients were stratified into two groups by tumour size: less than 5.0 cm and 5.0-7.0 cm in diameter. The large tumours were more advanced (higher T stage) and included a larger number of patients with less well differentiated tumours. Comparisons of morbidity are made in each dose group defined by tumour size. Early and late morbidity was carefully assessed during follow-up and was found to be unacceptably high in the group who received 57.5 Gy in 20 daily fractions.