ABSTRACT
Objective To examine the dosimetric advantages of three-dimensional (3D) computed tomography (CT)-guided interstitial brachytherapy (BT) for target volume and surrounding normal tissue in patients with locally advanced cervical cancer,and to provide a simple and effective clinical treatment approach.Methods A total of 52 patients who had poor tumor response to external beam radiotherapy (EBRT) with a residual tumor greater than 5 cm at the time of BT were included.The patients were treated by 3D CT-guided interstitial BT using a hybrid applicator comprised of uterine tandem and free metal needles.The high-risk clinical target volume (HR-CTV),intermediate-risk clinical target volume (IR-CTV),and organs at risk (OAR) were contoured.The total dose,including external beam radiotherapy and high dose-rate BT,was biologically normalized to conventional 2 Gy fractions (EQD2).D90and D100for both HR-CTV and IR-CTV,and D2 ccfor the bladder,rectum,and sigmoid were analyzed.Results The mean D90value for HR-CTV was 88.4±3.5 Gy.The D2 ccfor the bladder,rectum,and sigmoid were 81.1±5.6,65.7±5.1,and 63.1±5.4 Gy,respectively.D2 cc≤90 Gy for the bladder and D2 cc≤70 Gy for the sigmoid were observed in all the patients.D2 cc≤70 Gy for the rectum was observed in 89% of patients.Conclusions 3DCT-guided interstitial BT has a significant dosimetric advantage for target volume accompanied by few minor complications,and thereby may be clinically feasible for treating locally advanced cervical cancer.However,its long-term efficacy and possible toxicities will require further clinical observation.