Clinical outcomes of using 3D-printed applicators for high-dose-rate brachytherapy in gynecological malignancy

Purpose: To investigate the clinical outcomes and toxicities of using 3D-printed applicators for image-guided adap-tive brachytherapy (IGABT) in gynecological cancer patients. Material and methods: Fourteen patients with gynecological cancers, both primary and recurrent, treated with in-house 3D-printed applicators between 2021 and 2022 were included in the study, and their data were retrospectively reviewed. Timing and patterns of response to treatment were recorded. Kaplan-Meier estimates at 2 years post-treat-ment were analyzed to obtain local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), progres-sion-free survival (PFS), and overall survival (OS) rates. Actuarial rates of genitourinary (GU), gastrointestinal (GI), and skin and mucosal toxicities were also reported. Results: The median follow-up time for all patients was 27 (IQR: 15.4-32.5) months. Among the primary cases, 2 patients had cervical cancer and 3 had extra-mammary Paget's disease of the vulva. For the recurrent cases, all patients had vaginal relapses. The most common primary cancers were cervical cancer (44.4%) and ovarian cancer (33.3%). At 3 months post-treatment, 13 patients (92.9%) achieved a complete response (CR), and 1 patient (7.1%) showed a partial response (PR). The 2-year rates of LRFS, DMFS, PFS, and OS for primary/recurrent cases were 100%/74.07%, 100%/88.9%, 100%/64.8%, and 100%/88.9%, respectively. The actuarial rates of >= grade 2 acute GU and GI toxicities were 7.1% for both groups. For late GU and GI toxicities, the actuarial rates were 14.3% and 21.4%, respectively. In terms of skin and mucosal toxicities, 4 patients (28.6%) developed acute grade 3 toxicity, and 1 patient (7.1%) experienced persistent grade 3 vaginal toxicity. Conclusions: IGABT treatment using 3D-printed applicators for HDR brachytherapy in challenging cases due to incompatibility of the standard applicators with the patient's anatomy or highly advance disease, has demonstrated encouraging outcomes and acceptable toxicity profile