Late Rectal Complications Evaluated by Computed Tomography–Based Dose Calculations in Patients With Cervical Carcinoma Undergoing High-Dose-Rate Brachytherapy

• Published in: International journal of radiation oncology, biology, physics Vol. 69; no. 1; pp. 118 - 124
• Main Authors: Noda, Shin-ei, Ohno, Tatsuya, Kato, Shingo, Ishii, Takayoshi, Saito, Osami, Wakatsuki, Masaru, Tamaki, Tomoaki, Watanabe, Kazuhiro, Nakano, Takashi, Tsujii, Hirohiko
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2007
• Subjects: Adenocarcinoma - pathology; Adenocarcinoma - radiotherapy; Adult; Aged; Aged, 80 and over; Analysis of Variance; Biologically effective dose; BRACHYTHERAPY; Brachytherapy - adverse effects; Carcinoma, Adenosquamous - pathology; Carcinoma, Adenosquamous - radiotherapy; Carcinoma, Squamous Cell - pathology; Carcinoma, Squamous Cell - radiotherapy; CARCINOMAS; Cervical carcinoma; COMPUTERIZED TOMOGRAPHY; CT-based dose calculation; DOSE RATES; Female; Hematology, Oncology and Palliative Medicine; High-dose-rate intracavitary brachytherapy; Humans; ICRU; Late rectal complications; Middle Aged; MULTIVARIATE ANALYSIS; PATIENTS; RADIATION DOSES; Radiation Injuries - diagnostic imaging; Radiation Injuries - pathology; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Radiotherapy Dosage; RECTUM; Rectum - diagnostic imaging; Rectum - radiation effects; Relative Biological Effectiveness; Tomography, X-Ray Computed; Uterine Cervical Neoplasms - pathology; Uterine Cervical Neoplasms - radiotherapy; Late rectal complications; High-dose-rate intracavitary brachytherapy; Cervical carcinoma; Biologically effective dose; CT-based dose calculation
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2007.02.027

Purpose: To investigate the efficacy of dose calculations at the computed tomography (CT)-based rectal point (CTRP) as a predictive factor for late rectal complications in patients with cervical carcinoma who were treated with a combination of high-dose-rate intracavitary brachytherapy and external beam radiotherapy. Methods and Materials: Ninety-two patients with uterine cervical carcinoma undergoing definitive radiotherapy alone were retrospectively analyzed. The median follow-up time for all patients was 32 months (range, 13–60 months). The cumulative biologically effective dose (BED) was calculated at the rectal reference point as defined by the International Commission on Radiation Units and Measurements Report 38 (BED RP) and at the CTRP (BED CTRP). Late rectal complications were recorded according to the Radiation Therapy Oncology Group grading system. Results: The late rectal complications were distributed as follows: Grade 0, 68 patients (74%); Grade 1, 20 patients (22%); Grade 2, 4 patients (4%). Univariate analysis showed that BED RP, BED CTRP, RP dose/point A dose ratio, and CTRP dose/point A dose ratio were significantly correlated with late rectal complications ( p < 0.05). On multivariate analysis, patients with a rectal BED CTRP ≥140 Gy 3 presented with significantly greater frequency of rectal complications ( p = 0.031). Conclusions: The present results suggest that BED CTRP is a useful predictive factor for late rectal complications.