High Dose Rate Brachytherapy Boost After Chemoradiation in Rectal Cancer Patients: A Retrospective Study

Abstract

Background: The use of neoadjuvant chemoradiation has enhanced local control in rectal cancer patients. Objectives: The aim of this study was to evaluate the feasibility and efficacy of adding a high dose rate (HDR) brachytherapy (BRT) boost in locally advanced rectal cancer. Methods: This retrospective trial was conducted based on the medical records of patients with rectal cancer, who were referred to a tertiary hospital for neoadjuvant treatment. Fifteen patients who were treated with HDR brachytherapy boost after completion of external beam radiotherapy (EBRT) and concurrent chemotherapy were enrolled in the intervention group and 15 patients who were clinically matched (age, sex, stage, and distance of tumor from anal verge) were selected as the control group. EBRT schedule and concurrent chemotherapy regimen were similar in the two groups. The rate of pathological complete response (PCR), downstaging (T staging), and frequency of side effects were compared between the two groups of the study. Results: The mean age of patients was 57.97 ± 9.11 years and 18 patients (60%) were male. The results showed that T 3 and N 1 rectal cancer had the highest frequency among patients. Downstaging was observed in 66.7% and 80% of the control and intervention groups, respectively (P: 0.40). The rate of PCR was not different in the two groups (13.3% in both groups, P > 0.99). There were no significant differences in terms of treatment complications between the two groups, as well. Conclusions: HDR-BRT boost for rectal cancer is feasible and might improve downstaging in rectal cancer, but not PCR.