TOTAL SKIN ELECTRON-IRRADIATION IN MYCOSIS-FUNGOIDES DOSE AND FRACTIONATION CONSIDERATIONS

This study was undertaken to analyze the influence of total skin dose and dose-fractionation schedules on the response rate, survival and sk in toxicity of patients with mycosis fungoides [MF] treated with total skin electron irradiation [TSEI]. From 1979 to 1992, 40 patients with MF were treated with TSEI using a modified Christie Hospital techniqu e. Mean follow-up time was 48 months [median 20 months]. 37/40 patient s completed TSEI; three died due to non-treatment-related conditions d uring therapy. 34/37 [92%] treated patients achieved complete remissio n [CR] and 16/40 [40%] are alive with no evidence of disease. Over the years, changes in dose-fractionation schedules were made and correlat ed with the pattern of CR and skin toxicity. The 5-year actuarial surv ival [Stanford staging] was 84% in Stages IA-IB [all Stage IA patients are alive] and 59% in Stage II. The probability of survival of Stage III-IV patients was 30% at 30 months. Late skin toxicity was mild to m oderate in 60% and severe in 25% of patients. A reduction of the total dose and dose-per-fraction resulted in an acceptable CR rate and a si gnificantly lower toxicity. TSEI is effective in early stage MF. Skin control and late skin toxicity seem to be dose-fractionation-schedule related. For the early stages, the optimal treatment schedule seems to be 24-30 Gy to the whole skin surface in 2.4-3.0 Gy fractions, given twice weekly over a period of four to six weeks. Total doses of 24-30 Gy at 2.4-3.0 Gy per fraction yielded comparable skin control rates wi th lower skin toxicity.