Dosimetric study of three-dimensional image-quided brachytherapy combined with intracavitary/ interstitial brachytherapy in locally advanced cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To explore the dosimetric advantages of computed tomography-based and ultrasound-guided three-dimensional image-quided brachytherapy (3D-IGBT) combined with intracavitary/interstitial (IC/IS) brachytherapy for locally advanced cervical cancer.Methods A total of 45 patients with FIGO (2009) stage ⅠB2-ⅣA locally advanced cervical cancer who received radical external beam radiotherapy and 3D-IGBT combined with IC/IS brachytherapy in our hospital from 2013 to 2014 were analyzed.After the treatment with 192Ir-based IC/IS brachytherapy,patients had needles removed from the original images and received treatment only from IC radiation sources.Dosimetric differences in the planning D90 for high-risk clinical target volume (HR-CTV),D90 for intermediate-risk CTV (IR-CTV),and D2 cm3 for the bladder,rectum,sigmoid colon,and small intestines were determined and analyzed by paired t-test.Results A total of 260 after-loading treatment plans,including IC/IS treatment plans for 130 patients and IC treatment plans for 130 patients,were made.The D90 for HR-CTV and D90 for IR-CTV in the IC/IS brachytherapy group were significantly higher than those in the IC brachytherapy group (P =0.000;P =0.000).Moreover,the average D2cm3 values for the bladder and rectum were significantly reduced in the IC/IS brachytherapy group compared with those in the IC brachytherapy group (P =0.000;P =0.006).Conclusions The 3D-IGBT combined with IC/IS brachytherapy not only achieves a higher dose for the target volume,but also reduces the radiation dose to the bladder and rectum in the treatment of locally advanced cervical cancer.