Combined intracavitary and interstitial brachytherapy of cervical cancer using the novel hybrid applicator Venezia: Clinical feasibility and initial results

To report on first-in-human experience and the initial clinical results using the hybrid applicator Venezia (Elekta, Sweden) in the treatment of patients with locally advanced cervical cancer. Between March, 2017, and February, 2018, a total of 40 fractions were performed on patients undergoing definitive chemoradiation and brachytherapy (BT) for cervical cancer. A plan comparison was conducted evaluating the hybrid applicator with the clinically used intracavitary and interstitial (IC/IS) BT against a standard plan prescribed to Point A and a manually optimized plan using only intracavitary (IC) BT. Overall 80 treatment plans were retrospectively generated. The clinical use of the hybrid applicator system proved to be feasible in all 40 treatment fractions. The applicator consists of the IC tandem and two lunar-shaped ovoids forming a ring that serves as a template for defined parallel and oblique (12°) needle insertion. MRI preplanning was performed the day before the implant. One to six needles were placed per fraction, and overall a total of 66 needles were used. No complications such as bleeding or organ penetration occurred due to needle placement. Significant differences in IC/IS, Point A, and IC plans were derived for dose application to the target volume; D90 high-risk clinical target volume was 90.7 vs. 88.1 vs. 80.8 Gy (p = 0.008). Likewise, sparing of organs at risk differed significantly for bladder D2cc 79.4 vs. 91.8 vs. 79.2 Gy (p = 0.03) and rectum D2cc 58.7 vs. 67.3 vs. 62.5 Gy (p = 0.03). The clinical application of the Venezia applicator is feasible and allows significantly improved dose coverage while at the same time sufficiently sparing organs at risk.