High-dose-rate brachytherapy for cutaneous T-cell lymphoma involving complex skin sites

Mycosis fungoides (MF) is a highly radiosensitive tumor and low dose palliative radiotherapy is an essential treatment modality with excellent results. However, some skin sites with complex, oblique or very curved shape are difficult to treat with conventional radiotherapy techniques. We report our experience using HDR brachytherapy to treat MF in complex skin sites.

All patients who underwent HDR brachytherapy (HDR BT) for mycosis fungoides from 2014-2023 were included. Superficial brachytherapy molds such as the Freiburg flap applicator and 3D surface mold applicator were used. Following CT acquisition, the Oncentra treatment planning software was used to generate a treatment plan. Clinical response locally was assessed using the Olsen criteria and toxicities were recorded on the skin tumor unit database.

Thirty-nine (39) skin lesions within complex, and oblique and/or curved sites in 28 patients were treated with HDR BT. Local complete response rate is 100% with a mean follow up of 33 months. Sites treated were the face (n = 5), arms (n = 5), hands (n = 17), legs (n = 4), and feet (n = 8). Dose and fractionations used were 8 Gy/2F/2 days, 9 Gy/3F/3d, 12 Gy/3F/3d and 20 Gy/10F/2 weeks. Sixty percent were retreatment sites with a prior mean cumulative dose of 34 Gy (EQD2 α/β = 3). The mean D80% for all sites was 96.8% (range 85.6%-99.9%) with D0.1cc and D2cc to the involved skin 112.6% (range 101.5%-130.7%) and 102.5% (range 93.7%-117.3%) respectively. Complete response was achieved in 100%. Rate of G3 toxicity was 2.6% and G2 toxicity was 10.3%.

HDR BT is a safe and effective technique to treat MF lesions situated in regions of high obliquity and/or curvature with an acceptable toxicity rate.