High-dose-rate brachytherapy using Leipzig applicators for non-melanoma localized skin cancer

Brachytherapy and 3D printing for skin cancer: A review paper

Brachytherapy is a type of radiation therapy, in which a radiation source is placed directly or close to a tumor. It is commonly used to treat skin cancer, and enables precise irradiation treatment of affected area (planning target volume - PTV) while minimizing exposure dose to surrounding healthy tissue (organs at risk - OARs). Recently, the use of 3D printing has begun revolutionizing brachytherapy, as it allows manufacturing of custom-designed applicators for unique shape of skin topography, tumor, and surrounding tissues. Outcome of the combination of 3D printing and brachytherapy has several advantages over traditional treatment planning methods. Some of the advantages are intuitive, whereas others can be concluded from a literature overview as follows: 1) Possibility of developing patient-specific applicators that precisely match the shape of tumor area; 2) Reduction of the time required for applicator production, especially when custom-made devices are needed; 3) Reduction of manufacturing costs; 4) Treatment procedures improvement; 5) Improvement of safety measures accelerated by the development of smart materials (e.g., polymer filaments with admixture of heavy elements); 6) Possibility of nearly instant adjustment into tumor treatment (applicators can be changed as the tumor is changing its shape); and 7) Applicators designed to securely fit to treatment area to hold radioactive source always in the same place for each fraction. Consequently, tumor-provided dose is accurate and leads to effective treatment. In this review paper, we investigated the current state-of-the-art of the application of 3D printing in brachytherapy. A number of existing reports were chosen and reviewed in terms of printing technology, materials used, treatment effectiveness, and fabrication protocols. Furthermore, the development of future directions that should be considered by collaborative teams bridging different fields of science, such as medicine, physics, chemistry, and material science were summarized. With the indicated topics, we hope to stimulate the innovative progress of 3D printing technology in brachytherapy.

Customized 3D-printed molds for high dose-rate brachytherapy in facial skin cancer: First clinical experience

BACKGROUND AND OBJECTIVE

Radiotherapy of elderly, frail patients with facial skin cancer in proximity to critical organs is challenging. This is the first report on clinical experience with facial skin cancer treated by individualized 3D-printer-based mold high-dose-rate (HDR) brachytherapy (BT).

PATIENTS AND METHODS

Fifteen patients not eligible for radical surgery or definitive external beam radiotherapy (EBRT) were treated with 3D-printer-based mold HDR-BT. Patient selection and treatment were in accordance with multidisciplinary tumor board recommendations. Clinical response, toxicity and cosmesis were analyzed.

RESULTS

Median age was 77 years. Histology revealed squamous cell carcinoma in seven, basal cell carcinoma in five, melanoma in situ in one, Lentigo maligna in one, and melanoma in one patient, respectively. Median prescription dose was 39 Gy delivered in once-daily fractions of 3 Gy. After a median follow-up of 12.2 months, local recurrence was observed in one patient with melanoma in situ. Apart from one grade 4 cataract, no other > grade 2 late toxicity was documented.

CONCLUSIONS

HDR-BT with 3D-printer-based molds for facial skin cancer is a well-tolerated and safe treatment option for elderly, frail patients not eligible for radical surgery or definitive EBRT due to functional inoperability or tumor location.

High Dose Rate Brachytherapy in non - melanoma skin cancer - systematic review

Non-melanoma skin cancers (NMSC's) are the most common malignancies worldwide. Millions of new cases every year present challenge to healthcare systems. Recent years brought numerous new data concerning High Dose Rate (HDR) brachytherapy as treatment option for NMSC's. International guidelines do not recognize brachytherapy as a method of choice given lack of randomized trials, however many prospective and retrospective studies show promising results. Aim of the study was to present the efficacy of HDR brachytherapy, with analysis of its safety and adverse effects based on review of the English published medical full-text papers. Literature review of thirteen articles published between 1999 and 2021 was performed. Pubmed and Google Scholar databases were searched on October 2021 using keywords: ((Basal cell carcinoma) OR (squamous cell carcinoma) OR (non-melanoma skin cancer)) AND (HDR brachytherapy). Fourteen full text English articles with follow up over 1 year and study group over 50 patients were included into analysis. In analyzed material 2403 patients received High Dose Rate brachytherapy. Local control varied between 71 and 99%.Dominant reported cosmetic effect was good or very good. Results were cross-referenced with recent meta-analyses comparing brachytherapy to surgical excision, Mohs microsurgery and external beam radiotherapy. Radiodermitis is the main adverse effect of radiation treatment during and after radiotherapy. HDR brachytherapy emerges as potentially non-inferior treatment method providing very good reported cosmetic outcomes.