ESTRO 2025 - Abstract Book

S296

Brachytherapy – Head & neck, skin, eye

ESTRO 2025

Material/Methods: This is a retrospective cohort study. All consecutive patients who had early OCSCC (cT1-2N0M0) who received primary radiotherapy exclusively using interstitial brachytherapy between January 2000 and December 2020 were included. The primary outcome was local recurrence free survival (LRFS); secondary outcomes included regional recurrence free survival (RRFS), disease-specific survival (DSS), overall survival (OS), and treatment-related complications. Survival endpoints were analysed using the Kaplan-Meier method. All analyses were performed using the SPSS statistical software version 30.0. Results: A total of 38 patients with early OCSCC treated by interstitial brachytherapy was included, of which 20 patients (52.6%) received high dose rate (HDR) brachytherapy and 18 patients (47.4%) received low dose rate (LDR) brachytherapy. The median radiation dose given was 55 Gy (5.5 Gy per fraction, 2 fractions per day with a minimum of 6 hours in between) by HDR and 66.5 Gy by LDR. Patient demographics and tumour characteristics were summarised in Table 1. Most patients (86.8%) underwent elective neck dissection following primary interstitial brachytherapy.

At a median follow-up time of 11 years, 21 patients (51.2%) died. The LRFS was 86.1% at 3 years and 76.6% at 5 years; RRFS was 80.3% at 3 years and 77.2% at 5 years; DSS was 88.6% at 3 years and at 5 years; OS was 78.4% at 3 years and 75.7% at 5 years. During the period of follow-up, 11 patients (28.9%) developed local recurrence, among which 7 of them (63.6% who had local recurrence) were salvaged by surgery. A total of 8 patients (21.1%) developed regional recurrence, and 2 of them (25% who had regional recurrence) were salvaged by neck dissection. For