A patient‐based dosimetric study of intracavitary and interstitial brachytherapy in advanced stage carcinoma of the cervix

Abstract

Intracavitary brachytherapy (ICBT) and interstitial brachytherapy (IB) techniques are commonly practiced for treating carcinoma of the cervix, either alone or in combination with external beam radiotherapy. Both these brachytherapy techniques have their own advantages and limitations in terms of tumor coverage and normal tissue sparing. Limited studies have been reported comparing the dosimetric features of these two techniques, especially from a single institution. We carried out a prospective clinical dosimetric comparison between ICBT and IB for patients treated at one center to bring out the inherent dosimetric features of these to two techniques. The study was carried out on 26 patients treated with ICBT and 55 with IB using CT‐based planning. Of the 55 patients treated with IB, 27 included tandem source loading (IBT) and 28 without the tandem loading (IBWT). The high‐dose volumes covered by 200% and 180% isodose surfaces were considerably larger in ICBT as compared to IB, whereas the treated volume was larger in IB as compared to ICBT. The bladder and rectal doses were the highest in ICBT and IBWT, respectively. The larger treated volume in IB as compared to ICBT was mainly because patients with larger tumor volumes were generally considered for IB. The results also indicated that in interstitial brachytherapy, better rectal sparing was achieved by including the tandem for treatment delivery.PACS numbers: 87.53.Bn, 87.53.Jw, 87.55.D‐, 87.55.dk

Dosimetric Comparison of Fixed and Flexible Geometry ICRT Applicators in Patients Treated for Carcinoma Cervix

“…The TRAK values are also similar in both the cases as shown in Table 1. These values (4.91 and 4.93 mGy) are close to the value (5.1 mGy) reported by Bansal et al (2014) [15]. The tilt angle of the intrauterine tandem towards left or right side with respect to the patient midline was also noted to its effect on dose distribution.…”

“…The thickness value for the fixed applicator is similar to the one quoted by Bansal et al, i.e. 4.45 cm [15]. The thickness difference in the two types of geometries could translate into higher rectum/bladder dose but was not found to be so for all the cases.…”

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

“…Nevertheless, a biological correlation between HR-CTV hotspots and local control for cervical cancer is unknown. In our study, we could achieve median HR-CTV hotspots of greater than 62% (V 150 ) and 39% (V 200 ) by volume-based planning and were comparable to the data reported by other studies [ 51 , 52 ].…”

Dosimetric evaluation of the feasibility of utilizing a reduced number of interstitial needles in combined intracavitary and interstitial brachytherapy for cervical cancer

“…A study by Bansal et al. 18 showed that interstitial needles (number ranged from 18 to 26) combined with an intrauterine tandem resulted in significantly higher doses to 2 cm 3 of the bladder than intracavitary alone (Fletcher tandem and ovoids), with comparable doses to 2 cm 3 for the rectum and sigmoid. It supported our study to use a lesser number of needles to reduce the dose to the bladder 2 cm 3 , where they used 18–26 needles and this study tried to reduce the needles number to 6–10.…”

“…There were only 42 (17.9%) replans with bladder 2 cm 3 being failed among 234 replans from nine configurations to achieve the dose coverage compared to the full‐loading. A study by Bansal et al 18 . showed that interstitial needles (number ranged from 18 to 26) combined with an intrauterine tandem resulted in significantly higher doses to 2 cm 3 of the bladder than intracavitary alone (Fletcher tandem and ovoids), with comparable doses to 2 cm 3 for the rectum and sigmoid.…”