Water Bath Radiation for Extensive, Extremity-Based Cutaneous Disease of Mycosis Fungoides

Abstract Purpose Radiotherapy is an effective palliative treatment modality for cutaneous T-cell lymphomas such as mycosis fungoides (MF) due to its sensitivity to radiation. For patients with extensive skin involvement of the limbs, it is challenging to accommodate a number of clinical concerns: providing homogeneous dose to an irregular surface, minimizing the treatment time, and maintaining reproducible setups for multiple treatments. We utilized water as a tissue compensator to address all of these concerns. Case presentation A 66-year-old man with a history of stage IB mycosis fungoides previously treated with multiple prior therapies, including surface applicator high dose rate (HDR) brachytherapy. The disease then progressed to involve the right upper extremity distal to the prior treatment and much of the left upper extremity. In addition, he had recurrence of the prior right posterior thigh plaque, and face without scalp involvement. In order to avoid prolonged treatment time and inhomogeneous dose delivery, external beam radiation therapy using a water bath for tissue compensation was used to treat the upper extremities. We used a water tank and aligned each extremity to the center of the tank with custom-fit immobilization devices. A dose of 10 Gy in 2.5 Gy per fraction using 6 mega-voltage photons was prescribed to the mid-plane of the water tank. Two opposed lateral beams were used to obtain homogeneous dose across the water tank. Results The patient tolerated the treatment without toxicities. A complete response was observed during follow-ups at 6 and 12 weeks after treatment. Conclusions The patient reported improved function and cosmesis following treatment of his upper extremities with the water bath technique radiation therapy. Using a water bath as a tissue compensator was a fast and reproducible method for treatment of MF with circumferential cutaneous involvement of the extremity.