Surface mold brachytherapy for nonmelanoma skin cancer: Canadian patterns of practice

PURPOSE: We sought to describe the use of surface mold brachytherapy (SMBT) for nonmelanoma skin cancer in Canada. METHODS AND MATERIALS: A list of Canadian Association of Radiation Oncologists membership and provincial registries were used for a preliminary survey to identify radiation oncologists and physicists involved in the practice of SMBT. A detailed survey was sent electronically to individuals involved in treating with SMBT. RESULTS: Of 41 centers in Canada, 39 responded, with 7 centers indicating use of SMBT. Seven radiation oncologists and 5 physicists from 6 of 7 treating centers responded to the detailed survey, with an overall 75% individual response rate (12/16). General agreement was found regarding indications for SMBT which included irregular or curved surfaces, avoidance of deep structures, and requirement for small fields. There was consensus regarding some contraindications for SMBT such as tumor depth and size. Hypofractionated schedules were used in 5 of 6 centers and doses ranged from 50 Gy in 5 fractions once per week to 30 Gy in 10 fractions twice a day over 5 days. The most common dosimetric parameters for plan evaluation included D90, D95, D100, and maximum skin dose. CONCLUSIONS: A minority of Canadian centers practice SMBT. In centers practicing SMBT, general agreement exists on general indications for its use. Given the wide variation in dose and fractionation used and the rarity of the indication a phase 2 Canadian protocol would be invaluable.