Optimization of high-dose-rate intracavitary brachytherapy schedule in the treatment of carcinoma of the cervix

摘要

Purpose: At our institute, we use high-dose-rate (HDR) intracavitary brachytherapy (ICBT) schedule of 9. Gy per fraction for two fractions after external beam radiotherapy (EBRT) in patients with advanced carcinoma of the cervix. But American Brachytherapy Society recommends that individual fraction size should be less than 7. Gy per fraction in such patients. We present the results of comparison of our institution standard schedule with biologically equivalent dose of 6.8. Gy per fraction for three fractions in terms of local control, disease-free survival, and late toxicity. Methods and Materials: Between October 2003 and August 2007, 104 patients with carcinoma of the uterine cervix (Stages IIB and IIIB) were treated with EBRT and HDR ICBT. After EBRT, patients were randomized to one of the treatment arms. ICBT dose in Control Arm A (n= 52) was 9. Gy per fraction in two fractions, 1 week apart, and in Study Arm B (n= 52), it was 6.8. Gy per fraction in 3 fractions, 1 week apart. Results: The median followup was 31.48 months. The 3-year actuarial local control was 81.35% in Arm A and 65.18% in Arm B (p= 0.0423), and the 3-year actuarial disease-free survival was 64.97% in Arm A and 49.47% in Arm B (p= 0.0393). The 3-year actuarial risk of developing any Grade 3 or worse late toxicity was 7.47% in Arm A and 3.57% in Arm B (p= 0.2907). Conclusion: In our setup, HDR brachytherapy at 9. Gy per fraction in two fractions is safe and effective with good local control, survival, and manageable normal tissue toxicity.