Surface mould brachytherapy in a completely edentulous hard palate carcinoma using an innovative technique: One size does not fit all

Purpose
Surface mould brachytherapy (SMB) in edentulous hard palate cancer patients remains a technical challenge due to issues in prosthetic retention and reproducibility. We present a novel technique for SMB in a completely edentulous patient with a second primary squamous cell carcinoma (SCC) of the hard palate, previously treated with external beam radiotherapy.

Material and methods
A 73-year-old edentulous male presented with a 1 cm × 1 cm superficial lesion in the hard palate on the right side, staged as cT1N0M0. Given his prior irradiation and surgical ineligibility, high-dose-rate (HDR) SMB was planned. A unique, interlocking maxillo-mandibular acrylic prosthesis with interlocking struts was designed in collaboration with prosthodontics to provide mould stability. Four 6-F nylon catheters were embedded into the maxillary mould, spaced 1 cm apart. Treatment was delivered using an iridium-192 source at 4 Gy per fraction, twice daily (6-hour interval), to a total dose of 52 Gy over 7 days.

Results
The patient developed grade 3 acute mucositis two weeks after treatment, but tolerated the therapy well without the need for hospitalization. Mucositis resolved with conservative management. At a 24-month follow-up, the patient remained disease-free, with preserved speech and swallowing functions, excellent mucosal healing, and no late complications or recurrences observed.

Conclusions
This case highlights the feasibility and effectiveness of using a customized interlocking acrylic mould for SMB in edentulous patients. The technique ensured reliable prosthetic retention, precise catheter placement, and optimal dose delivery, resulting in favorable oncologic and functional outcomes. Incorporating prosthodontic principles into the workflow of brachytherapy broadens its application for complex head and neck cancer cases.