Background: There is limited published evidence regarding the efficacy of total skin electron beam radiation for patients with the diffuse erythrodermic form of mycosis fungoides.
Methods: Forty-five patients with erythrodermic mycosis fungoides were managed at McMaster University in Hamilton, Ontario, Canada (n=34), and at Yale University (n=11) between 1970 and 1996. All received radiation without neoadjuvant, concomitant, or adjuvant therapies. The median age was 67 years (range, 42-84 years). The male-to-female ratio was 2.2. Fifteen received radiation for the treatment of newly diagnosed disease. There were 28 with Stage III (T4 N0-1 M0), 13 with Stage IVA (T4 N2-3 M0), and 4 with Stage IVB (T4 N0-3 M1) disease, and 21 had blood involvement. The median radiation dose was 32 gray (Gy) (range, 4.8-40 Gy). The median treatment time was 21 days (range, 3-125 days). A technically more intense method of radiation (32-40 Gy and 4-6 MeV electrons) was administered to 23 patients.
Results: All patients responded. The rate of complete cutaneous remission was 60%, with 26% remaining progression free at 5 years. Remission was associated with more intense radiation (P=0.014 in multivariate analysis with adjustment for blood and staging information). With the more intense radiation, 74% attained remission, with 36% remaining progression free at 5 years. For 8 patients with Stage III disease without blood involvement, all entered remission, with 69% remaining progression free at 5 years. Twenty of 30 deaths were related to mycosis fungoides. The median overall survival was 3.4 years, with a 10-year estimate of 28%. The median cause specific survival was 5 years, with a 10-year estimate of 43%. Both overall and cause specific survival were associated with an absence of blood involvement (both P<0.03 in multivariate analysis). Age was not a significant factor. Toxicities of radiation were acceptable when radiation was administered over 6-9 weeks at 5 fractions per week.
Conclusions: Total skin radiation is an efficient monotherapy for patients with erythrodermic mycosis fungoides. With more intense radiation, the rate of cutaneous remission is 74%, and 27% remain progression free at 10 years. Radiation may be most efficacious in Stage III, with no blood involvement. When there is blood, lymph node, or visceral involvement, combined modality therapies should be explored.