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

BACKGROUND AND PURPOSE 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. MATERIAL AND METHODS 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. RESULTS 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). CONCLUSIONS The implementation of 3D-ICR in radiotherapy for cervical cancer can reduce the incidence of severe LRB and may improve the LC rate.