Low-dose-rate vs. high-dose-rate intracavitary brachytherapy for carcinoma of the cervix: The University of Alabama at Birmingham (UAB) experience

Abstract

Purpose: To review the clinical outcome retrospectively of cervical cancer patients treated definitively with either high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy.

Methods and materials: One hundred sixty patients (44 Stage I, 83 Stage II, and 33 Stage III) were treated from 1990 to 2000 with curative intent for carcinoma of the cervix. One hundred three LDR patients were compared to 57 HDR patients. Two groups were treated during the same period. An external beam dose of 45 Gy to the entire pelvis was delivered at 1.8 Gy per fraction to most patients before the first intracavitary insertion in both groups. Brachytherapy was delivered in one to two LDR implants or four to five HDR implants at 6 Gy per fraction. The prescribed dose to Point A for LDR was at least 80-85 Gy. Patient characteristics were similar for each cohort. Point A doses were similar for each stage. The primary endpoints assessed were survivals and failure sites. Endpoints were estimated using the Kaplan-Meier method and comparisons between treatment groups were performed using the log-rank test.

Results: The median followup was 48 months for the LDR group and 59 months for the HDR group. For all stages combined and stage for stage in both groups, there was no statistically significant difference in locoregional control, cause-specific survival, and overall survival for LDR compared with HDR. Locoregional control and overall survival were 78% and 60% for LDR compared to 76% and 55% for HDR at 3 years, respectively (p = 0.96 and p = 0.48). Median cause-specific survival values for LDR vs. HDR were 71 and 81 months, respectively (p = 0.62). The cause-specific survival for LDR patients was 62% compared with 59% for HDR patients at 3 years. For Stage IB2, II, and III LDR patients, cause-specific survival rates were 62%, 67%, and 45%, compared to 67%, 57%, and 33% for HDR at 3 years, respectively (p = 0.75, p = 0.95, and p = 0.48). For patients with a recorded site of first failure, the most common site was locoregional (56%) and then distant metastases (26%). Eight patients who were cancer free developed late complications requiring surgical intervention. Two patients were in the HDR group (3.5%) and 5 in the LDR group (4.8%).

Conclusions: Similar outcome was observed for LDR compared with HDR intracavitary brachytherapy for the entire cohort. In this review, HDR group was not inferior to LDR group in advanced stages. This is likely because our patients were treated with brachytherapy after a high dose of external pelvic radiotherapy in both LDR and HDR patients.