Radiation-induced impairment of urinary bladder function. Assessment of micturition volumes.
PURPOSE: The present investigation was initiated in order to study the feasibility of repeat micturition volume measurements for the determination of acute variations in urinary bladder function in radiotherapy patients. PATIENTS AND METHODS: Thirty-seven consecutive patients with malignancies of the prostate (11), rectum (9), corpus uteri (11), or cervix uteri (6) were included in this pilot study. All patients were treated according to standard irradiation protocols. All patients were asked to present with maximum bladder filling for each radiation treatment. After irradiation, patients were weighed before and after micturition, and the weight difference was assumed to reflect the micturition volume. RESULTS: No systematical variations in bladder capacity could be assessed during treatment for uterine tumors. In rectum carcinoma patients, a decrease in micturition volume by about 20% was observed between weeks 2 and 5 which, however, was not statistically significant; subsequently, normal to supra-normal values were measured. In patients treated for prostate cancer, volumes were reduced from week 2; in weeks 5 to 6, minimum values of approximately 70% of the control volumes were seen, which represent a significant reduction (p < 0.05). CONCLUSIONS: Functional changes represent the majority of side effects of radiation therapy in the urinary bladder. The assessment of urinary bladder function by pre- and post-micturition weighing is a feasible and sensitive method to objectively determine radiation-induced changes. This method may be applied for the documentation of acute radiotherapy side effects.