Analysis of dosimetry and clinical efficacy of intracavitary/interstitial brachytherapy in Ⅲ B cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To compare the dosimetry and efficacy of intracavitary brachytherapy (ICBT) and intracavitary/interstitial brachytherapy (IC+ ISBT) based on CT image guidance in the treatment of stage Ⅲ B cervical cancer. Methods:Clinical data of 93 patients with stage Ⅲ B cervical cancer treated in Department of Radiotherapy of Jilin Cancer Hospital from June 2014 to February 2017 were analyzed retrospectively. According to the results of Gynecological examination and pelvic MRI before brachytherapy, confirming the size of residual tumor and the degree of parauterine infiltration, all patients were divided into the ICBT and IC+ ISBT groups. The D 90%, D 100%, V 100% and D 2cm 3 of bladder and rectum were compared, and the short-term and long-term efficacy was observed between two groups. Results:The median follow-up time was 60 months. The 5-year local control rate, distant metastasis-free survival rate and overall survival rate of all patients were 83%, 71% and 68%, respectively. Compared with the ICBT group, HR-CTV D 90% in the IC+ ISBT group was all more than 85 Gy, while there was no significant difference between two groups ( P=0.188). The D 2cm 3 of bladder and rectum in the IC+ ISBT group was significantly decreased by 7 Gy and 8 Gy (both P<0.01), and the distant metastasis-free survival rate was significantly improved ( P=0.009). The 5-year local control rate in the HR-CTV volume>60 cm 3 in the IC+ ISBT group was significantly higher than that in the IC group ( P=0.029). Conclusion:For patients with Ⅲ B cervical cancer, IC+ ISBT can not only ensure target coverage, but also significantly reduce the incidence of distant metastasis and the dose of organs at risk, and significantly improve the local control rate of large tumors.