ESTRO 2025 - Abstract Book

S295

Brachytherapy – Head & neck, skin, eye

ESTRO 2025

2622

Digital Poster High-dose-rate interstitial brachytherapy for lip cancer

Zoltán Takácsi-Nagy 1,2 , Örs Ferenczi 1 , Georgina Fröhlich 3,4 , Ferenc Oberna 5 , Csaba Polgár 1,2 , Tibor Major 1,2 1 Centre of Radiotherapy, National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary. 2 Department of Radiotherapy, Semmelweis University, Budapest, Hungary. 3 Centre of Radiotherapy, National Institute of Oncology, Budapest, Hungary. 4 Department of Biophysics, Eötvös Loránd University, Budapest, Hungary. 5 Head and Neck Cancer Multidisciplinary Centre, National Institute of Oncology, Budapest, Hungary Purpose/Objective: High-dose-rate (HDR) irradiation has become increasingly popular in the interstitial brachytherapy (BT) of lip tumours over the last decade. In this paper we present the results of patients treated with this modality at the National Institute of Oncology, Budapest. Material/Methods: A total of 23 patients (T1-3N0) with a mean age of 68 years (range: 37-87) - treated between 2014 and 2023 - were included in this study. The indications for HDR-BT were as follows: primary treatment (n=12) or adjuvant treatment (n=11). Postoperative care was due to R1 resection or ≤ 2 mm surgical margin or perineural spread. The histology was squamous cell carcinoma in 20 cases, adenocystic carcinoma in 1 case and non-Hodgkin's lymphoma in 2 cases. Flexible plastic catheters were implanted in the lip (3 for 3, and 2 for 19 cases), the treatment planning was CT-based, and the irradiation was performed with an HDR Ir-192 source. The mean prescribed dose was 43 Gy (range: 27-45 Gy), usually given in 15 fractions of 3 Gy, twice daily. Results: During the mean follow-up period of 54 months (range: 12-136 months) the 5-year local and regional control, overall survival and cancer-specific survival were 95%, 91%, 81% and 95%, respectively. The volume of the planning target volume (PTV) was 4 cm 3 (range: 0.5-22.2 cm 3 ), the reference dose coverage (V100) 91.4 % (range: 73.1-97.6%) and the D2cm 3 for mandible 0.6 Gy (range: 0.2-2 Gy). Grade 1, 2, and 3 acute toxicities were observed in 35%, 48%, and 17%, respectively. Late toxicity was not detected. Cosmetic results were excellent in 35%, good in 57%, and poor in 8%. Conclusion: HDR-BT with 15x3 Gy fractionation is an effective and safe treatment for lip carcinomas with excellent local control and cosmetic outcomes, and appears to be an effective modality for the treatment of early lip tumours in both definitive and postoperative therapy.

Keywords: lip, brachytherapy, HDR

2782

Mini-Oral Interstitial brachytherapy for early oral cavity squamous cell carcinoma: long-term treatment outcomes from a single tertiary oncology centre Carol Hing Yee Wong, James Chung-Hang Chow Clinical Oncology, Queen Elizabeth Hospital, Hong Kong, China Purpose/Objective: To evaluate the long-term efficacy of interstitial brachytherapy for the treatment of early oral cavity squamous cell carcinoma (OCSCC). Long-term toxicities were also evaluated.