Purpose: To determine the prognosis of new patients with T1-4N0-1B0M0 mycosis fungoides treated with total skin electron beam radiation.
Methods and materials: 25 consecutive patients received 30 Gy with 3 or 4 MeV electrons in 1977-1980; 121 received 35 Gy with 4 MeV in 1980-1992. Response rates, relapse-free survival, and overall and cause-specific survivals were assessed by explicit criteria. The relationships of T, N, gender, age, and radiation technique to prognosis were investigated by regression statistics.
Results: The average age was 55 years and the male:female ratio was 1:4. Forty-four percent were T1N0 and 34% were T2N0. The overall complete response rate was 82%, and lower T status, more radiation, and female gender were independently and positively associated with response. Median follow-up was 5.2 years. T1 patients who entered remission had a higher relapse-free survival compared to T2 through T4 patients. Thirty-four percent of T1 patients remained relapse-free at 6 years, compared to fewer than 20% of T2-4 patients. For all 146 patients the median overall survival was not reached at 15 years. Only 8 of 29 deaths were related to mycosis fungoides and these were significantly associated with higher T. The 54 T1N0 patients who had 35 Gy had a 10-year mycosis fungoides-specific survival of 100%.
Conclusion: Total skin electron beam radiation gives good results with T1N0B0M0 disease. T3-4 disease is less likely to respond, it relapses more quickly, and it implies a poorer survival, but radiation offers palliation. T2 responds like T1, but relapses like T3-4. T2 also implies an intermediate survival. These results have implications for staging, informed consent, optimizing radiation treatment, and clinical trials.