A comparison of the efficacy and complication rates of low dose-rate versus high dose-rate brachytherapy in the treatment of uterine cervical carcinoma.

Purpose: To compare the outcome and complication rates for treatment of uterine cervical carcinoma with low dose-rate (LDR) vs. high dose-rate (HDR) brachytherapy at the University of Wisconsin Comprehensive Cancer Center (UWCCC).

Methods And Materials: One-hundred ninety-eight evaluable patients with cervical carcinoma, Stages IB to IIIB, treated with curative intent with a combination of megavoltage teletherapy and LDR brachytherapy from 1977 to 1988 were the subject of an initial review. In 1989, a HDR treatment program was initiated where all patients with cervical carcinoma were subsequently treated with a combination of HDR brachytherapy and teletherapy. Using the linear-quadratic model (LQ), the dose and schedule of HDR brachytherapy and teletherapy were designed to give similar tumor control and late effects as LDR therapy. Technically, the HDR schedule required meticulous attention to treatment geometry to limit severe late effects. Forty patients treated with the HDR program with 2-4 year follow-up were reviewed and compared to the previous LDR patient group. The LDR and HDR treatment groups were comparable with regards to age, weight, stage distribution, bulk of disease, and histology.

Results: No significant difference in survival was found between the LDR and HDR groups with 3-year actuarial overall survival being 66% and 77%, respectively. Three-year actuarial pelvic control rates were similar at 80% and 77% for the LDR and HDR groups, respectively. No significant difference in late treatment complications requiring hospitalization or surgery was found between the two treatment groups with a complication rate of 10% (20/198) for the LDR patients and 2.5% (1/40) for the HDR patients.

Conclusion: As predicted by our LQ calculations, treatment results for LDR and HDR brachytherapy were similar with respect to survival, pelvic control and late complications in the treatment of cervical carcinoma. The HDR brachytherapy program at the UWCCC appears to be a safe and effective alternative to LDR therapy in the treatment of cervical carcinoma.