GSOR07 Presentation Time: 5:30 PM

Abstract

Purpose

There are no international guidelines for optimal needle insertion method during interstitial intracavitary brachytherapy (IS-ICBT) for cervical cancer. We aimed to investigate the clinical feasibility and added value of Three-dimensional computed tomography angiography (3D-CTA) reconstruction of the origin of the uterine artery and its clinical significance guidance to optimize needle insertion in IS-ICBT using the interstitial cylinder applicator and Aarhus ring and Vienna Ring and to evaluate acute complications after needle insertion.

Materials and Methods

We enrolled 85 patients with locally advanced cervical cancer (stage II to IIIC2) which were evaluated for in IS-BT at the Oncology Institute Ion Chiricuță Cluj-Napoca, Romania Department of Radiation Oncology. We performed for every patient a 3D-CTA before the needle implantation, in order to visualise uterine artery and its ascending/descending branches . Using 3D-CTA and reconstructed images of adaptive iterative dose resolution 3D (AIDR 3D) with display field of view (D-FOV), which are suitable for arteries with large and small diameters, and created the fusion images. Created images allowed the visual observation of vessel branch and by this technique we could determine optimal needle locations and insertion lengths based on the vessels position in order to avoid needle penetration of the artery or the proximity organs. The needle-channel axis was used as a reference to determine needle insertion. After the needle insertion based on the 3D-CTA another CT was performed for the contouring of the needles. Postinsertion adverse events were recorded during inpatient stay and at 6-week followup.

Results

Median followup time was at least 3 months. All patients were initially treated with external beam radiation therapy, median dose of 45 Gy. A total of 170 insertions were performed. No patient presented massive hemorrage because due to the 3D-CTA we were able to know exactly where the uterine artery or the branches are positioned and we avoided the penetration.When we performed the planning CT, there were no radiological evidence of needle intrusion(s) into the pelvic organs and no gastrointestinal complications were found. In this study, only 5 patients with grade 1 thrombocytopenia had minor vaginal bleeding after needle removal which was autolimited. The insertion of the needles was made under general anesteshia. Our results indicated that dizziness, nausea, and vomiting happened to be a constant side effect in this patients because of the general anestesia, but the side effects were acceptable. According to our findings, the most frequent acute adverse impact experienced by patients upon awakening from anaesthesia was pain. Patients experienced varying degrees of discomfort during the brachytherapy procedure. This could lead patients to reposition and alter the position of the applicator and needles, potentially influencing the therapeutic outcome.

Conclusions

The proposed technique using 3D-CTA it's very valuable and clinically feasible in evaluating the position of the uterine artery for the optimal needle location and insertion and has a major role in avoiding massive hemorrage. Furthermore, no repeated CT scans were required with the proposed technique to adjust the needles. Needle intrusion into the OARs was not observed in any of the patients. Most of the complications were anestesia related and might influence the therapeutic outcome.