Implementing a simulation-based curriculum for hybrid intracavitary/interstitial brachytherapy using a new, commercially available, US/MR/CT-compatible gynecologic phantom.

PURPOSE: To establish a simulation-based workshop for teaching hybrid intracavitary/interstitial (IC/IS) brachytherapy skills using a new, commercially available US/CT/MRI-compatible gynecologic phantom prototype. METHODS AND MATERIALS: The VIOMERSE gynecological trainer phantom consisted of tissue-like colloid material and was US, CT, and MRI-compatible. We designed a hands-on workshop incorporating the phantom prototype to teach skills for hybrid IC/IS brachytherapy including pre-implant planning, procedural steps of implant placement, and post-implant evaluation. The workshop impact was evaluated with pre- and post-workshop surveys and responses were analyzed with Wilcoxon matched-pairs signed-rank test. RESULTS: Thirteen residents, divided into small groups, attended one of three separate 1-h workshop sessions held during the gynecologic education block. Workshop steps included IC applicator placement, tumor mapping and pre-planning desired location and depth of needles for hybrid IC/IS application, IS needle labelling and insertion, image review of needle placements, comparison of IC-alone versus IC/IS brachytherapy plans. Responses to questions ascertaining knowledge, confidence, and ability in planning and executing hybrid IC/IS procedures all demonstrated significant improvement from pre- to post-workshop. In response to whether the session was an effective learning experience, all residents rated the workshop with a score of 9 (n = 1) or 10 (n = 12) out of 10, with a score of 10 indicating "strongly agree." CONCLUSIONS: Implementation of a hybrid IC/IS brachytherapy workshop utilizing a new, commercially-available phantom prototype was successful, with clear, subjective benefit for the residents in our program. This experience may inform continued efforts towards standardizing brachytherapy curricula across programs and increasing trainee exposure to interstitial procedures.

Clinical Outcomes of MRI-Guided Adaptive Brachytherapy for Each Fraction in Locally Advanced Cervical Cancer: A Single Institution Experience.

Purpose: This study aims to evaluate clinical outcomes of MRI-guided adaptive brachytherapy (MR-IGABT) for each brachytherapy fraction in patients with locally advanced cervical cancer (LACC). Methods and Materials: A retrospective analysis was performed on 97 consecutive patients with LACC treated with 44.0-50.4 Gy external beam radiotherapy (EBRT) ± concurrent platinum-containing chemotherapy followed by 4 × 7 Gy MR-IGABT between September 2014 and April 2019. Intracavitary (IC)/interstitial (IS)/hybrid intracavitary and interstitial (IC/IS) brachytherapy was used in MR-IGABT. Brachytherapy planning and dose reporting followed the GEC-ESTRO recommendations. Clinical outcomes including overall survival (OS), cancer-specific survival (CSS), progression-free survival (PFS), local control (LC), and treatment-related toxicity evaluated by the RTOG criteria were analyzed. Kaplan-Meier and univariable and multivariable Cox regression analyses were used to analyze the prognostic factor. Results: Median follow-up was 21.1 months. Median dose to 90% (D90) of the high-risk clinical target volume (HR-CTV) was 91.7 Gy (range 76.7~107.2 Gy). Two-year OS, CSS, PFS, and LC were 83.5%, 84.1%, 71.1%, and 94.8%, respectively. Four patients (4.1%) suffered from grade 3 late gastrointestinal radiation toxicity, and no other grade 3 or greater radiation toxicity occurred. Initial HR-CTV was an independent factor of OS (p = 0.001, HR = 1.018/cm3), PFS (p = 0.012, HR = 1.012/cm3), and LC (p = 0.011, HR = 1.028/cm3). The HR-CTV D90 (p = 0.044, HR = 0.923/Gy) was an independent factor of PFS. Age was an independent factor of LC (p = 0.010, HR = 1.111/year). Conclusion: For patients with LACC, MR-IGABT was effective and safe. It showed favorable LC, OS, and minimal toxicity. Moreover, initial HR-CTV, HR-CTV D90, and age were significant prognostic factors.