Dose-volume parameters and clinical outcome of CT-guided freehand high-dose-rate interstitial brachytherapy for cervical cancer

摘要

Currently,image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer.In this study,we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-doserate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach.Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer.Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied.With a median of 5 (range,4-7) implanted needles for each patient,the median dose of brachytherapy alone delivered to 90％ of the target volume (D90) was 45 (range,33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range,20-36)Gyα/β10 for intermediate-risk clinical target volume (IR-CTV).The percentage of the CTV covered by the prescribed dose (V100) of HR-CTV with brachytherapy alone was 81.9％-99.2％ (median,96.7％).With an additional dose of external beam radiotherapy (EBRT),the median D90 was 94 (range,83-104) Gyα/β10 for HR-CTV and 77 (range,70-87) Gyα/β10 for IR-CTV; the median dose delivered to 100％ of the target volume (D100) was 75 (range,66-84) Gyα/β10 for HR-CTV and 65 (range,57-73) Gyα/β10 for IR-CTV.The minimum dose to the most irradiated 2 cc volume (D2cc) was 73-96 (median,83) Gyα/β3 for the bladder,64-98 (median,73) Gyα/β3 for the rectum,and 52-69 (median,61) Gyα/β3 for the sigmoid colon.After a median follow-up of 15 months (range,3-24 months),two patients experienced local failure,and 1 showed internal lilac nodal metastasis.Despite the relatively small number of needles used,CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.