Clinical implementation of interstitial brachytherapy in early-stage oral cancer in a newly commissioned tertiary cancer center: Challenges and initial experience

Abstract

Purpose: High-dose-rate (HDR) interstitial brachytherapy (ISBT) is a curative treatment option for head and neck cancer patients. However, its overall utilization has been declining, particularly in newer cancer setups. This study investigated challenges in ISBT implementation, and reported initial outcomes of early-stage oral cancer patients in a newly established tertiary cancer center.

Material and methods: After reviewing guidelines and addressing administrative requirements, ISBT program was launched. Key steps in the process included establishing brachytherapy suite, staff training, and optimizing workflows. Alongside standard protocols, additional procedures, such as clinical drawing templates, intra-oral ultrasound, and intra-oral spacers were implemented. From August 2020 to July 2022, 18 patients with early-stage (cT1-2N0M0) oral cancer (tongue = 13, lip = 3, buccal mucosa = 2) received treatment with either ISBT alone (n = 3) or external beam radiotherapy (EBRT), followed by ISBT with HDR cobalt-60 source (n = 15). Treatment characteristics, oncological outcomes, and morbidity profiles were analyzed.

Results: The median age of the cohort was 55 years (range, 29-75 years), with two-thirds of males. The majority had T1 stage (72.2%), with infiltrative growth pattern (72.2%). All patients with oral tongue cancer, 1 lip and 1 buccal mucosa cancer, received elective nodal irradiation with EBRT, followed by ISBT, achieving a total median EQD₂ of 74 Gy. The remaining 3 patients (2 with lip and 1 with buccal mucosa primary) received ISBT alone. Post-treatment complete response was observed in 17 patients (94.4%), with no cases of acute toxicity > grade 2. At a median follow-up of 32 months, an overall 3-year local-regional control and overall survival rates were 67.9% and 72.7%, respectively. One patient developed grade 3 myelopathy, and one grade 3 osteoradionecrosis.

Conclusions: Implementing ISBT in a newly established cancer center is feasible and effective for early-stage oral cancer, providing moderate oncological outcomes with manageable toxicity profile.

Keywords: head and neck cancer; interstitial brachytherapy; oral cancer.

Fig. 1

Challenges involved in implementation of brachytherapy program in oral cancer

Fig. 2

A) Clinical drawing template used for documentation of disease in oral tongue cancer patient. B) Clinical drawing at initial evaluation. C) Corresponding patient’s clinical photograph at brachytherapy. D) Clinical drawing at brachytherapy evaluation. E) Corresponding patient’s clinical photograph at brachytherapy

Fig. 3

A) Fabricated spacer for tongue cancer by using cold cure acrylic resin. B) Intra-oral fitting of acrylic shield in tongue cancer patient in lower jaw on the left side. C) Using of copper film over spacer for improved identification in planning CT scan for a patient with upper lip primary. D) Placement of intra-oral spacer in patient in upper jaw for upper lip primary case

Fig. 4

Images of a tongue cancer patient demonstrating ISBT dose distribution. A) With intra-oral spacer (marked in cyan), CTV (red), and B) mandible (brown) abutting intra-oral spacer. C) Avoidance of high-dose regions in the mandible with a use of spacer. D-F) Dose color-wash in sagittal, axial, and coronal sections, respectively

Fig. 5

Overall loco-regional control of patients treated with interstitial brachytherapy with or without EBRT