Abstract: Background and purpose: The radiation therapy is the main treatment of cervical cancer. In order to investigate the efficacy and toxicity of the 3D image-guided brachytherapy for cervical cancer, we analyzed dose-volume histogram (DVH) dose distribution and clinical data from 31 cases of cervical cancer treated with three dimensional brachytherapy. Methods: From May. 2013 to Dec. 2014, 31 cervical cancer cases with FIGO stage Ⅱa-Ⅳ received comprehensive treatment in our department. High risk-clinical target volume (HR-CTV) was 400-600 cGy per fraction, and totally 4-6 fractions for each patient. A total of 152 times 3D-CT guided brachytherapy was performed with ¹⁹²Ir high-dose-rate afterloader. We calculated the doses with EQD2 and analyzed the data on HRCTV D90, bladder D2cc, sigmoid D2cc, rectum D0.1cc and rectum D2cc of both the external-beam radiotherapy and CT-guided brachytherapy. The efficacy and toxicity were evaluated by RTOG/EORTC and RECIST (version 1.1) guideline. Results: There was no third degree reaction occurring on bladder, rectum or sigmoid. Two patients developed second degree chronic rectal bleeding 3 months after the completion of radiotherapy which were well controlled by medications. The tumor complete remission rate (CR) was 93.55% (29/31) 1-3 months after the treatment. Local control rate (LCR) rate was 93.55% (29/31) one year after the treatment, whereas disease-free survival rate (DFS) was 90.32% (28/31). Conclusion: The 3D CT-guided brachytherapy combined with external radiation for locally advanced cervical cancer showed positioning accuracy with an adequate dose distribution to the target area. The treatment made the OR dose visible, controllable and credible. It improved the treatment of patients with increased tolerance and avoided the severe radiation reactions. Thus, the combination therapy may greatly improve the quality of life for patients, and ought to be promoted.

Key words: Cervical cancer, Image-guided, 3D brachytherapy, Efficacy, Toxicity