Individualized 3D printing for skin cancer brachytherapy: Development, implementation, clinical applications, and treatment assessment

Purpose:
This study outlined the prevalent use of brachytherapy in skin cancers, such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The importance of customized applicator fabrication for optimal treatment delivery was highlighted, focusing on adaptable devices tailored to individual patient anatomy, often facilitated by 3D printing technology. The purpose of this work was to investigate the association of medical science and 3D printing in customized applicator fabrication for brachytherapy, leveraging the advancements in fabrication techniques to enhance treatment precision and patient outcomes.

Material and methods:
The study enrolled five patients with tumor lesions unsuitable for surgical intervention, situated across various anatomical locations, such as earlobe, temple, hand, and cheek. Customized applicators were fabricated via 3D printing (fused deposition modeling) for each patient, followed by radiotherapy protocol delivering a total dose of 51 Gy in 17 fractions. Patient assessments during and post-radiotherapy were done by radiation oncologist using RTOG scale as well as dermatological evaluations with dermatoscopy and reflectance confocal microscopy. Methodologically, applicators were 3D-printed using fused deposition modeling technology. Printing parameters were optimized in Prusa Slicer software, ensuring precise control in printout shape correlated with treatment efficacy.

Results:
This study examined the therapeutic outcomes of brachytherapy in five patients with inoperable skin cancer lesions. Utilizing customized 3D-printed applicators, the patients underwent brachytherapy regimen delivering a cumulative dose of 51 Gy in 17 fractions. The evaluation with RTOG scale revealed varied treatment responses, with complete remission achieved in all cases. Reflectance confocal microscopy showed post-treatment normalization of epidermal morphology and notable scar formation. Optical profilometry demonstrated consistent micro-structures on the applicator surfaces, without compromising treatment efficacy. These findings indicated the potential of 3D-printed applicators in optimizing brachytherapy outcomes in skin cancer management.

Conclusions:
Our study demonstrates the effectiveness of 3D-printed applicators in treating inoperable skin cancer lesions with high precision. In personalized fabrication, optimal conformity with anatomical features was achieved, resulting in complete remission in all patients. This approach minimizes treatment-related side effects and enhances overall patient outcomes, suggesting a promising future for 3D printing technology in skin cancer treatment applications. Further research and clinical validation are needed to establish 3D printing as a standard practice in skin cancer treatment.