Computed Tomography Guided Brachytherapy With Hybrid Applicators: An Effective Curative Treatment for Vaginal Cuff Recurrences.

Abstract

Purpose: This study evaluated the clinical feasibility of hybrid brachytherapy and the benefits of computed tomography (CT) guidance for optimizing applicator position and needle placement via Utrecht or Venezia applicators in the curative treatment of vaginal cuff recurrence.

Methods and materials: Sixteen previously operated patients with gynecological cancer treated with hybrid brachytherapy for vaginal cuff recurrence from 2018 to 2022 were included. The applicators were selected according to vaginal diameter and tumor location. CT scans were conducted before and after needle insertion. The high-risk clinical target volume (CTV-HR), including residual disease and suspicious regions, as well as normal tissues, was contoured. The dosimetry goal was to ensure that the reference isodose (100%) adequately covered the CTV-HR while minimizing overlap with organs at risk. The needle shifts were assessed according to their locations. Outcome measures, including disease-free survival and overall survival, were analyzed.

Results: A total of 64 fractions were administered, with Utrecht applicators used for 62.5% (n = 40). The median equivalent doses in 2 Gy fractions (EQD2 D90) for 90% of the CTV-HR and intermediate-risk CTV were 87.64 Gy (57.45-97.78 Gy) and 69 Gy (31.33-76.73 Gy), respectively. Among the 696 possible needle positions, 419 interstitial needles (60%) were successfully inserted. The median number of needles per fraction was 6 (range, 1-12). Needle shifts occurred in 93% of the patients, predominantly in the anteromedial direction, with a mean magnitude of 0.21 ± 0.14 cm. The median follow-up was 14 months, with a 90% local tumor control rate and an 85% overall survival rate over 2 years, without severe side effects.

Conclusions: Despite challenges in treating vaginal cuff recurrence in patients with gynecological cancers, hybrid brachytherapy provides an effective and personalized approach. Although needle shifts are common, they do not significantly impact dosimetric outcomes, highlighting the method's adaptability and reliability.