Aspects of dosimetry and clinical practice of skin brachytherapy: The American Brachytherapy Society working group report

Abstract

Purpose: Nonmelanoma skin cancers (NMSCs) are the most common type of human malignancy. Although surgical techniques are the standard treatment, radiation therapy using photons, electrons, and brachytherapy (BT) (radionuclide-based and electronic) has been an important mode of treatment in specific clinical situations. The purpose of this work is to provide a clinical and dosimetric summary of the use of BT for the treatment of NMSC and to describe the different BT approaches used in treating cutaneous malignancies.

Methods and materials: A group of experts from the fields of radiation oncology, medical physics, and dermatology, who specialize in managing cutaneous malignancies reviewed the literature and compiled their clinical experience regarding the clinical and dosimetric aspects of skin BT.

Results: A dosimetric and clinical review of both high dose rate ((192)Ir) and electronic BT treatment including surface, interstitial, and custom mold applicators is given. Patient evaluation tools such as staging, imaging, and patient selection criteria are discussed. Guidelines for clinical and dosimetric planning, appropriate margin delineation, and applicator selection are suggested. Dose prescription and dose fractionation schedules, as well as prescription depth are discussed. Commissioning and quality assurance requirements are also outlined.

Conclusions: Given the limited published data for skin BT, this article is a summary of the limited literature and best practices currently in use for the treatment of NMSC.

Keywords: Basal cell carcinoma; Biological equivalent dose; Clinical target volume; Electronic brachytherapy; Gross target volume; High dose rate; Ir-192; Nonmelanoma skin cancer; Planning target volume; Squamous cell carcinoma.