High-dose-rate Interstitial Brachytherapy with Computed Tomography-based Treatment Planning for Patients with Locally Advanced Uterine Cervical Carcinoma

The aims of this study were to carry out a dose volume analysis of high-dose-rate interstitial brachytherapy with computed tomography-based treatment planning and to investigate the treatment outcome of patients with locally advanced bulky and/or irregularly shaped uterine cervical carcinoma. Between July 2003 and December 2007, 15 patients were treated with external beam radiation therapy and high-dose-rate interstitial brachytherapy with or without intracavitary brachytherapy. Seven patients were treated with interstitial brachytherapy alone, and 8 were treated with combined use of intracavitary and interstitial brachytherapy. A comparison of the volume and dose parameters with intracavitary and interstitial brachytherapy in patients who received both treatments showed that the median D90 of the high-risk clinical target volume per fraction was 4.4 Gy with intracavitary brachytherapy and 5.6 Gy with interstitial brachytherapy, and the median V100 was 66% with intracavitary brachytherapy and 85% with interstitial brachytherapy. The median D2cc of the bladder with intracavitary and interstitial brachytherapy per fraction was 5.5 Gy and 4.7 Gy, respectively, and the median D2cc of the rectum with intracavitary and interstitial brachytherapy was 5.9 Gy and 4.1 Gy, respectively. The median follow-up time was 37 months, and the overall and progression-free survival rates for all patients at 3 years were 78% and 51%, respectively. The actuarial 2-year and 3-year locoregional control rates were 80% and 71%, respectively. Dose distribution was improved with image-based interstitial brachytherapy, and satisfactory local control was achieved for patients with locally advanced uterine cervical carcinoma in which intracavitary brachytherapy may result in a suboptimal dose distribution.