Low dose rate vs. high dose rate brachytherapy in the treatment of carcinoma of the uterine cervix: a clinical trial.

PURPOSE: This study is a prospective randomized clinical trial undertaken at our center to compare low dose rate versus high dose rate intracavitary brachytherapy for the treatment of carcinoma uterine cervix.

METHODS AND MATERIALS: From June 1986 to June 1989, 482 patients with previously untreated invasive squamous cell carcinoma of the uterine cervix were entered into the study. After an initial clinical examination and investigative work-up the patients were staged according to FIGO staging system. Depending upon the stage of the disease, the size of the local growth and the local cervical anatomy, the patients were divided into two main groups. In group I patients, the predominant treatment was by intracavitary therapy and in group II patients, the predominant therapy was by external beam radiation. In both the groups at the time of intracavity brachytherapy the patients were alternately randomized to receive either low dose rate or high dose rate brachytherapy. There were thus two hundred forty-six patients in the low dose rate group and two hundred thirty-six patients in the high dose rate group. The patients were analyzed for local control, 5 years survival and late radiation morbidity.

RESULTS: Stage for stage the local control rates in the low dose rate group and high dose rate group were similar. The overall local control achieved in the low dose rate group was 79.7% as compared to 75.8% in the high dose rate group. The 5 years survival figures in the low dose rate and high dose rate group were also comparable. In Stage I, it was 73% for low dose rate patients and 78% for high dose rate patients, for Stage II it was 62% and 64% respectively and for Stage III patients it was 50% and 43%. The only statistically significant difference was found in the incidence of overall rectal complications which was 19.9% for the low dose rate group as compared to only 6.4% for the high dose rate group. However, the more severe grade 3-4 complications were not significantly different between the two groups (2.4% vs. 0.4%, respectively). The bladder morbidity in both the groups was similar.

CONCLUSION: Thus high dose rate intracavitary brachytherapy is an equally good alternative to conventional low dose rate brachytherapy in the treatment of carcinoma of the uterine cervix.