Low-dose total skin electron beam therapy as a debulking agent for cutaneous T-cell lymphoma: an open-label prospective phase II study

Background Total skin electron beam therapy (TSEBT) is a powerful treatment for cutaneous T-cell lymphoma (CTCL). Based on the occurrence of relapses with low radiation doses, doses of 30-36 Gy are commonly used but most patients still eventually relapse and repeat treatment courses are limited due to the cumulative toxicity. Complete response (CR) rates are about 60-90% for T2-4 stages with a 5-year relapse-free survival of 10-25% for stages IB-III. Objectives To evaluate prospectively the efficacy of low-dose TSEBT (10 Gy) in terms of complete cutaneous response rate, overall response rate and response duration in CTCL. Methods Ten patients with stage IB-IV mycosis fungoides (MF) were treated in an open-label manner with four fractions of TSEBT 1 Gy weekly to a total skin dose of 10 Gy. Treatment responses were assessed at 1 and 3 months after treatment and subsequently at least every 6 months for a total period of 2 years or to disease relapse or progression. Results Patients achieved an overall response rate of 90%. The rate of CR or very good partial response (VGPR; < 1% skin affected with patches/plaques) was 70%. The median response duration was 5 2 months (range 83-469 days) for CR and VGPR. Adverse effects were generally mild to moderate in severity. Conclusions Low-dose TSEBT (10 Gy) gave a satisfactory response rate and was well tolerated in patients with MF stage IB-IV. Future studies should determine if the combination of low-dose TSEBT with other agents could increase the rate of CR and response duration.