Correlations of dose and time-dose-fractionation factors (TDF) with treatment results and side effects in cancer of the uterine cervix

Treatment results and side effects were analyzed for 57 patients with stage IB-IIIA cancer of the uterine cervix who received external beam radiotherapy combined with intracavitary insertion of cesium-137 sources. The total dosage and time-dose-fractionation (TDF) factors were calculated at point A and at points of maximum exposure in the rectum and bladder. The overall 5-year survival was 62%, and 78% of the complete responders were free of disease at 5 years. A total of 12 patients (21%) developed rectal complications. Two patients (4%) had rectal fibrosis and proctitis; seven cases of rectal bleeding occurred (12%), and 3 patients (5%) developed rectovaginal fistulas. There was no correlation between dose and TDF at point A and treatment failure or appearance of rectal complications. However, the occurrence of radiation damage in the rectum was consistently associated with high values of TDF when they were calculated in the region of maximal exposure in the rectum. The results suggest that TDF may be a useful parameter for predicting radiation damage in combined external beam and intracavitary treatment of cervical cancer.