Patient-Specific 3D-Printed HDR Surface Brachytherapy for Basal Cell Carcinoma in Older Patients: Prospective Feasibility and Imaging Response

BACKGROUND: Basal cell carcinoma (BCC) is frequent in older adults, many of whom are poor surgical candidates, especially for curved, cosmetically sensitive facial sites. High-dose-rate (HDR) surface brachytherapy is effective, but standard flat applicators may fit poorly and increase dose heterogeneity. Patient-specific 3D-printed applicators could improve conformity, yet geriatric BCC data are limited. OBJECTIVE: To assess feasibility and 12-month outcomes of personalized 3D-printed HDR surface brachytherapy in geriatric patients with BCC. METHODS: In this prospective single-arm study, 15 patients aged ≥65 years with histologically confirmed BCC (predominantly facial) unsuitable for surgery received HDR surface brachytherapy using custom 3D-printed applicators. Treatment delivered 51 Gy in 17 fractions with CT-based planning. Repeat CT evaluated applicator fit/reproducibility and target coverage. Acute skin toxicity was graded by RTOG. At 12 months, response was assessed clinically and dermoscopically; cosmesis and quality of life (DLQI) were recorded. RESULTS: All patients completed treatment. Positioning was highly reproducible (mean setup error <1 mm) with >90% target dose coverage. At 12 months, all lesions achieved complete remission with no local recurrence on dermoscopy. Acute reactions were mostly mild (73% grade 1), with 13% grade 2 and 13% grade 3; no grade 4 toxicity or serious adverse events occurred. Cosmesis was favorable, and DLQI improved (mean 10.5 pre-treatment vs 2.9 at 1 year; p < 0.01). CONCLUSIONS: Personalized 3D-printed HDR surface brachytherapy appears feasible and well tolerated in this small, monocentric cohort of older patients with BCC, with favorable 1-year local control and quality-of-life improvement when surgery is contraindicated. However, the limited sample size and single-center design represent limitation, and the observed benefit should be regarded as suggestive rather than definitive.