Total Skin Electron Irradiation and Sequential Malignancies in Mycosis Fungoides Patients: Longitudinal Study

Aims To determine the role of total skin electron irradiation (TSEI) as a cause of second malignancies in mycosis fungoides patients. Materials and methods Mycosis fungoides patients referred to TSEI were followed in a longitudinal study. Other diagnosed malignancies were obtained after cross-matching with the Israel National Cancer Registry database. Results Between 1974 and 2010, 197 patients were treated: 134 (68%) men, 63 (32%) women; mean age 58 ± 17years. Topical/systemic treatment was given to 134 (68%) patients. TSEI was given to 104 (68.9%) patients. Seven (4.6%) received sub-TSEI and 40 (26.5%) received focal electron irradiation fields. Forty-six (23%) patients did not receive radiotherapy. The second primaries rate was 6.7 times higher in male mycosis fungoides patients and 13.1 times higher in female mycosis fungoides patients than in the general Israeli population. Malignant melanoma developed in eight patients after radiotherapy, in one patient without irradiation. The skin-related cancer rate after irradiation versus no irradiation was higher (P = 0.018). Combination radiotherapy with psoralen + ultraviolet A and/or nitrogen mustard yielded 11 cases of skin cancer versus no cases without irradiation. Conclusions Mycosis fungoides patients have a high incidence of sequential malignancies. TSEI is associated with higher ‘skin-related cancer’ rates. Close longitudinal follow-up of mycosis fungoides patients is obligatory.