Long-term clinical outcomes of non-melanoma skin cancer patients treated with electronic brachytherapy

Purpose:
High-dose-rate electronic brachytherapy (eBx) is a non-surgical treatment option for non-melanoma skin cancer (NMSC) patients. This study assessed long-term effectiveness and safety of eBx for the treatment of NMSC.

Material and methods:
A chart review was conducted to identify subjects who had five or more years since their last eBx treatment fraction. Subjects meeting these criteria were contacted to determine their interest in participating in a long-term follow-up study. Those who agreed, underwent a follow-up visit where consent was obtained, and their lesions were clinically assessed for recurrence and long-term skin toxicities. History and demographic data were retrospectively collected, and treatment method was verified.

Results:
183 subjects with 185 lesions were enrolled into this study at four dermatology centers in two practices in California. Three subjects in the analysis were less than 5 years from the last treatment to follow-up visit. All lesions were stage 1 basal cell carcinoma, squamous cell carcinoma, or squamous cell carcinoma in situ. Recurrence rate for the 183 subjects was 1.1%. Long-term skin toxicities were reported in 70.0% of the subjects. Hypopigmentation grade 1 was observed in 65.9% of the lesions, telangiectasia grade 1 was seen in 22.2%, scarring grade 1 in two subjects (1.1%), hyperpigmentation grade 1 in two subjects (1.1%), and induration grade 2 in one patient (0.5%). The induration grade 2 was located on the upper back and did not limit instrumental activities of daily living (ADLs).

Conclusions:
Electronic brachytherapy for the treatment of non-melanoma skin cancer is safe and effective, showing excellent long-term 98.9% local control through a median follow-up of 7.6 years (n = 183), with minimal long-term toxicities.