Radiotherapy of advanced mycosis fungoides: indications and results of total skin electron beam and photon beam irradiation.

Background: The goals of this retrospective study of advanced mycosis fungoides are (1) to describe the indications of a combination of total skin electron beam and photon beam irradiation and (2) to analyze the results of total body or segmental photon irradiation for patients with extension beyond the skin.

Methods: From January 1975 to December 1995, 45 patients with pathologically-confirmed mycosis fungoides or Sézary syndrome received a combination of TSEB and photon beam irradiation for advanced disease: 34 males and 11 females, mean age 61 years (range 27-87 years). The mean follow-up was 111 months (range 18-244 months, median 85 months). Whole-skin irradiation treatment to a depth of 3-5 mm with a 6-MeV electron beam was produced by a linear accelerator to a total dose of 24-30 Gy in 8-15 fractions, 3-4 times a week. In cases of thick plaques or tumors that were beyond the scope of low energy electron beams or for treating nodal areas (especially in the head and neck area or axilla involvement), regional irradiation (RRT) with Co-60 photon beams was followed by whole-skin electron beam irradiation (15 patients). In cases of diffuse erythrodermia, Sézary syndrome, nodal or visceral involvement, total body irradiation was delivered with a 25-MV photon beam using a split-course regimen to prevent hematological toxicity (22 patients). The first course consisted of 1.25 Gy delivered in ten fractions and 10 days. Subsequently, patients received TSEB. Four to 6 weeks after TSEB, they received a second course of 1.25 Gy. The cumulative TBI dose ranged from 2.5 to 3 Gy in about 3 months. Hemi-body irradiation (HB) with Co-60 (and a bolus) was given in cases of multiple regional tumors with large and thick infiltration of the skin to a dose of 9-12 Gy (using fractions of 1-1.5 Gy/day) which, once flattened, were boosted with whole-skin electron beam therapy (8 patients).

Results: At 3 months, the overall response rate was 75% with 23/45 (51%) patients in complete response and 24% in partial response; one patient had stable lesions and 1 patient presented progressive disease. The overall response rate was 81% for T3 patients, 61% for T4, 79% for N1 and 70% for N3. The complete response rate was 67% for T3 and 28% for T4. Sixty-four percent of N1 patients and 41% of N3 had a complete response. The 5-year actuarial overall survival was 37% for T3 and 44% for T4 (P = 0.84). Patients with clinically abnormal lymph nodes that were pathologically negative (N1) presented a 5-year survival of 63%. Patients with pathologically positive lymph nodes (N3) experienced a 5-year survival rate of 32% (P = 0.040).

Conclusions: TSEB provides an excellent quality of life by reducing itching and discharge from the skin. Patients with more advanced disease may be treated and cured by the addition of photon beams in combination with TSEB. A selection of patients with advanced skin disease and regional extension may be cured by a combination of TSEB and photon beam irradiation. The regional treatment allows the use of electrons after the reduction of the plaques or thick tumors and a prophylactic irradiation of the adjacent nodal area.