3D CT-based high-dose-rate brachytherapy for cervical cancer: clinical impact on late rectal bleeding and local control.

Abstract

To identify the impact of 3D CT-based high-dose-rate intracavitary radiotherapy (ICR) on late rectal bleeding (LRB) and local control (LC) in patients with cervical cancer. The outcomes of 97 consecutive patients treated with 3D CT-based ICR (3D-ICR) were compared with those of 133 consecutive historical patients with conventional 2D brachytherapy planning (2D-ICR). The median follow-up periods were 41 and 56 months for the 3D and 2D groups, respectively. The overall rectal bleeding rate was similar between the groups (42% for 3D-ICR vs. 44% for 2D-ICR); however, the incidence of severe LRB was higher in the 2D-ICR group than in the 3D-ICR group (13% vs. 2%, respectively; p=0.02). In multivariate analysis, the factors associated with severe LRB were tumor >4 cm (12% vs. 3%) and 2D-ICR (10% vs. 2%). The LC rates were 97% and 91% for 3D-ICR and 2D-ICR, respectively (p=0.14); the progression-free survival rate was 80% for both groups. A significant difference in the LC rates between the two groups was observed in patients with larger tumor sizes with the tumor diameter of over 4 cm (98% vs. 81% by 3D-ICR vs. 2D-ICR, respectively; p=0.02). The implementation of 3D-ICR in radiotherapy for cervical cancer can reduce the incidence of severe LRB and may improve the LC rate.