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ImportancePatients with recurrent or unresectable skin cancers have limited treatment options. Diffusing alpha-emitter radiation therapy (DaRT), a novel solid tumor management strategy using alpha-particle interstitial brachytherapy, may address this challenge.ObjectiveTo evaluate the feasibility and safety of using DaRT to manage recurrent or unresectable skin cancers.Design, Setting, and ParticipantsThis prospective cohort study of patients who received a 2-week to 3-week treatment course and were followed up for 24 weeks after treatment during 2021 and 2022 at 2 sites in the US. Patients with malignant skin tumors or soft tissue tumors were recruited if they had limited treatment options for tumors recurrent after prior surgery or external beam radiotherapy or unresectable tumors.InterventionPatients underwent DaRT to deliver a physical dose of 10 Gy (equivalent weighted dose of 200 CGE) to the tumor.Main Outcomes and MeasuresFeasibility of the DaRT procedure was evaluated based on the ability of investigators to successfully deliver radiation to the tumor. Patients were followed up for adverse events (AEs) for 24 weeks and for tumor response by physicians’ physical examination and imaging 12 weeks after device removal.ResultsThis study included 10 participants with recurrent or unresectable skin cancer (median [IQR] age, 72 [68-75] years; 6 males [60%]; 4 females [40%]). Six patients (60%) had recurrent disease, and 4 (40%) had tumors that were deemed unresectable. Tumors were located on the nose, chin, eyelid, scalp, neck, trunk, and extremities. Median (range) tumor volume before treatment was 2.1 cm3 (0.65-12.65 cm3). The mean (SD) prescription dose coverage of the gross tumor volume was 91% (2.8%) with all tumors having coverage of 85% or more. No device-related grade 3 AEs were noted. Common AEs were grade 1 to 2 erythema, edema, and pruritus. At 12 weeks following treatment, there was a 100% complete response rate. Nine of 10 complete responses (90%) were confirmed by CT imaging.Conclusions and RelevanceThis cohort study suggests the feasibility and preliminary safety of DaRT in the management of recurrent or unresectable skin cancers. The favorable safety profile and high response rates are promising. A US trial for marketing approval based on this pilot study is under way.Trial RegistrationClinicalTrials.gov Identifier: NCT04377360

Purpose To present the American Brachytherapy Society (ABS) guidelines for plaque brachytherapy of choroidal melanoma and retinoblastoma. Methods and Materials An international multicenter Ophthalmic Oncology Task Force (OOTF) was assembled to include 47 radiation oncologists, medical physicists, and ophthalmic oncologists from 10 countries. The ABS-OOTF produced collaborative guidelines, based on their eye cancer–specific clinical experience and knowledge of the literature. This work was reviewed and approved by the ABS Board of Directors as well as within the journal's peer-reivew process. Results The ABS-OOTF reached consensus that ophthalmic plaque radiation therapy is best performed in subspecialty brachytherapy centers. Quality assurance, methods of plaque construction, and dosimetry should be consistent with the 2012 joint guidelines of the American Association of Physicists in Medicine and ABS. Implantation of plaque sources should be performed by subspecialty-trained surgeons. Although there exist select restrictions related to tumor size and location, the ABS-OOTF agreed that most melanomas of the iris, ciliary body, and choroid could be treated with plaque brachytherapy. The ABS-OOTF reached consensus that tumors with gross orbital extension and blind painful eyes and those with no light perception vision are unsuitable for brachytherapy. In contrast, only select retinoblastomas are eligible for plaque brachytherapy. Prescription doses, dose rates, treatment durations, and clinical methods are described. Conclusions Plaque brachytherapy is an effective eye and vision-sparing method to treat patients with intraocular tumors. Practitioners are encouraged to use ABS-OOTF guidelines to enhance their practice.