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Interstitial brachytherapy (ISBT) is considered one of the standard modalities for curative treatment of early stage oral cancers. However, optimal utilization of this modality in the era of multidisciplinary cancer care can be challenging, especially in a newly commissioned comprehensive cancer centre. We present our experience and challenges in implementing ISBT for head neck cancers and early outcomes of oral tongue cancer treated with ISBT in the first two years of commissioning the brachytherapy services.

ISBT services were commissioned in August 2020 at our institution. Challenges faced during implementation of ISBT in head and neck cancers were enumerated. Case records of all early stage head and neck cancer patients treated at our institution with ISBT between September 2020 and September 2022 were retrospectively reviewed. 

The technical challenges included commissioning of the Cobalt after-loader, dedicated brachytherapy procedure room, setting up of BT applicator sets (implantation kit, nylon tubes, beads etc.), orientation and training of ancillary staff. 

Though incidence of HN cancers is high, proportion of patients deemed suitable for BT was low, due to advanced stage at presentation (Table 1). Multidisciplinary tumor board consultation before treatment initiation is quintessential for identifying patients who can potentially benefit from BT. Discussing organ preservation approaches with patients also helped increase BT utilization, especially for tongue cancer.

Among the 14 patients with tongue cancer, median tumor size was 2 cm, and clinical stage was T1 in 10 and T2 in 4 patients. All patients received prophylactic irradiation to bilateral neck nodes along with primary, using VMAT (50Gy/25#/5 weeks), followed by HDR Interstitial BT boost by CT based planning after a median gap of 22 days (range, 15-42 days). Most patients required implantation in two planes, with 9 to 15 catheters (median, 11). Median BT prescription dose was 22.5 Gy in 5 fractions in 3 days (range, 20 to 22.5 Gy), and cumulative EQD2 was 77.5Gy (10). Mandibular BT doses were limited to a median of 4.4 Gy (D 0.1 cc) and 3.15 Gy (D 1cc) per fraction. 

At a median follow up of 16 months (range, 3 to 23 months), 11 out of 14 are alive and disease free. Among the three who had recurrence, one had local recurrence, one had locoregional and one developed local recurrence

with lung metastases. No long-term toxicity was observed during the limited follow up, except in one who developed early superficial asymptomatic mandibular radio-necrosis (mandibular dose of 81.1 Gy EQD2 and follow-up of 6;months)  and managed conservatively.

Brachytherapy for Head and neck cancers, tongue cancers poses a unique challenge and requires a dedicated multi-disciplinary team approach. Our preliminary experience suggests modest outcome with acceptable toxicities especially in oral tongue cancers.