# Interstitial Brachytherapy for Early Oral Cavity Squamous Cell Carcinoma: Long-Term Treatment Outcomes From a Single Tertiary Oncology Center

## TL;DR

This study shows that brachytherapy is a safe and effective treatment for early-stage oral cancer, with good long-term results.

## Contribution

The study provides long-term outcomes of interstitial brachytherapy for early oral cavity squamous cell carcinoma, supporting its use as an alternative to surgery.

## Key findings

- Interstitial brachytherapy achieved 76.6% five-year local recurrence-free survival for early oral cavity squamous cell carcinoma.
- Treatment-related complications were low, with 10.5% experiencing osteoradionecrosis and 7.9% persistent tongue ulcers.
- Over half of local and regional recurrences were successfully salvaged by surgery or neck dissection.

## Abstract

Purpose/objective

This study aimed to evaluate the long-term efficacy of interstitial brachytherapy for the treatment of early oral cavity squamous cell carcinoma (OCSCC).

Materials and methods

This retrospective review included consecutive patients with early OCSCC (cT1-2N0M0) who underwent primary radiotherapy exclusively by interstitial brachytherapy between January 2000 and December 2020. The primary outcome was local recurrence-free survival (LRFS); secondary outcomes included regional recurrence-free survival (RRFS), disease-free survival (DFS), disease-specific survival (DSS), overall survival (OS), and treatment-related complications. Incidence of late treatment-related complications is reported.

Results

Thirty-eight patients with early OCSCC underwent interstitial brachytherapy during the study period, of which 20 (52.6%) underwent high dose rate (HDR) brachytherapy with a median dose of 55 Gy and 18 (47.4%) underwent low dose rate (LDR) brachytherapy with a median dose of 66.5 Gy. Elective neck dissection was performed in 33 (86.8%) patients. At a median follow-up time of 11.8 years, the three-year and five-year LRFS were 86.1% and 76.6%, respectively. RRFS was 80.2% at three years and 77.1% at five years; DFS was 73% at three years and 62.2% at five years; DSS was 88.6% at three years and at five years; OS was 78.4% at three years and 75.7% at five years. Local recurrence occurred in 10 (26.3%) patients, with six (60%) salvaged by surgery. Regional recurrence occurred in eight (21.1%) patients, and three (37.5%) were salvaged by neck dissection. Treatment-related complications included persistent tongue ulcer in three (7.9%) patients and osteoradionecrosis of the jaw in four (10.5%) patients.

Conclusion

Interstitial brachytherapy for early OCSCC yielded acceptable long-term local control and safety data. While radical surgery continues to be the standard of care for OCSCC, interstitial brachytherapy remains an effective and safe alternative for selected patients with early-stage disease.