Successful treatment of tumor stage mycosis fungoides with total skin helical tomotherapy

Total skin electron beam therapy (TSEBT) is a treatment option for mycosis fungoides (MF). In Japan, it has been rarely performed because of the time required for each treatment, physical burden on patients, and difficulties in providing uniform dosimetry. In recent years, helical tomotherapy, an intensity‐modulated radiation therapy that applies helical computed tomography technology, has been used to treat cancer. Total skin helical tomotherapy (TSHT) has been suggested as a promising alternative to TSEBT for patients with MF, but there are few reports from Japan. We used TSHT to treat a 28‐year‐old Japanese woman with tumor stage MF. She achieved complete remission with TSHT (12 Gy in six fractions over 6 days) and remained in remission for 32 months without additional treatment. Treatment‐related grade 4 myelosuppression was observed, but resolved with blood transfusions and subcutaneous injection of granulocyte colony stimulating factor. Other adverse events were tolerable. Although careful attention should be paid to myelosuppression, TSHT might be a useful treatment option for MF.