ESTRO 2025 - Abstract Book

S289

Brachytherapy – Head & neck, skin, eye

ESTRO 2025

416

Digital Poster Updated outcomes of HDR brachytherapy using 3D-printed custom applicators for BCC in challenging head and neck regions. Artur J. Chyrek 1,2 , Adam Z. Kluska 1 , Wojciech M. Burchardt 1,2 , Grzegorz Bielęda 3,2 , Adam Chicheł 1 1 Brachytherapy Department, Greater Poland Cancer Centre, Poznań, Poland. 2 Electroradiology Department, University of Medical Sciences, Poznań, Poland. 3 Medical Physics Department, Greater Poland Cancer Centre, Poznań, Poland Purpose/Objective: Since 2020, we have integrated 3D printing technology to create patient-specific applicators for high-dose-rate (HDR) brachytherapy to treat basal cell carcinoma (BCC) located in anatomically challenging regions of the head and neck area [1,2]. This study provides an updated evaluation of the clinical effectiveness and safety of this approach. Material/Methods: Between June 2020 and September 2022, 26 patients with 31 BCC tumors were treated using customized 3D printed applicators. Tumor response and early toxicity were assessed 4 weeks post-treatment using the RTOG scale, with subsequent evaluations every 3-6 months to monitor long-term local control and late toxicity. Results: The cohort consisted of 20 women and 6 men, with a median age of 77 years [IQR 70–83]. Of the 31 treated tumors, 24 were staged as T1 (77%), 4 as T2 (13%), and 3 as T3 (10%) per UICC/AJCC TNM v7. Tumor locations included the nose (81%), ear (7%), and peri-orbital area (13%). HDR brachytherapy served as the primary treatment for 18 lesions (58%) and as a salvage treatment for 13 lesions (42%) following previous surgery. All tumors were classified as high risk for recurrence according to NCCN guidelines. The median follow-up was 32 months [IQR 24.27–36.3]. All tumors received the prescribed dose of 42–45 Gy, delivered in 6–11 fractions over 6–27 days. The response rate and local control were both 100%. Acute skin toxicities were reported as erythema (G1 - 36%), patchy desquamation (G2 – 7%), confluent desquamation (G3 - 16%), and tumor breakdown with bleeding (G4 - 32%). Late toxicities included skin discoloration or depigmentation (G1 - 52%) and small telangiectasia (G2 - 23%). Conclusion: This updated analysis demonstrates that HDR brachytherapy with 3D-printed applicators provides excellent tumor control with minimal toxicity for BCC in challenging head and neck regions, reaffirming the clinical benefits of this technique.

Keywords: 3D-printed applicators. HDR. BCC.

References: 1. Bielęda, G., Marach, A., Boehlke, M., Zwierzchowski, G., and Malicki, J. (2021). 3D-printed surface applicators for brachytherapy: a phantom study. Journal of Contemporary Brachytherapy, 13(5), pp.549-562. 2. Bielęda, G., Chicheł, A., Boehlke, M., Zwierzchowski, G., Chyrek, A., Burchardt, W., Stefaniak, P., Wiśniewska, N., Czereba, K., and Malicki, J. (2022). 3D printing of individual skin brachytherapy applicator: design, manufacturing, and early clinical results. Journal of Contemporary Brachytherapy, 14(2), pp.205-214.