Radiation therapy eradicates malignant T cells and is associated with improved survival in early-stage mycosis fungoides
Menée à partir de 20 échantillons de lésions cutanées prélevés sur 18 patients atteints d'un mycosis fongoïde traité par radiothérapie à faible dose de rayonnements ou par application locale de stéroïdes, puis menée à partir de données de survie globale portant sur 47 patients complémentaires, cette étude met en évidence l'intérêt de la radiothérapie pour éradiquer les lymphocytes T malins et améliorer la survie chez les patients dont la maladie est à un stade précoce
Purpose: Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma. Skin-directed treatments often improve but do not cure MF skin lesions. The purpose of this study was to 1) assess whether remission was associated with malignant T cell clone depletion at treated sites using either low dose radiation therapy (LDRT, 8 Gy) or topical steroids and 2) assess whether a clone-ablative therapy, like LDRT, is associated with overall survival in high-risk early-stage CTCL patients. Experimental Design : Pre- and post-treatment biopsies from 20 lesional skin samples of 18 MF patients who received either 8 Gy LDRT (n=16) or topical steroids (n=4) underwent high-throughput T-cell receptor sequencing (HTS) of the TCRB gene to quantify the malignant T cell clone. For the retrospective chart review, overall survival of 47 high-risk early-stage patients was compared between patients who did or did not receive radiation. Results : LDRT eradicated the clone in 5/16 lesions and reduced it >90% in 11/16; there were no recurrences in these lesions. Patients treated with topical steroids appeared to clinically improve but the malignant clone persisted. We found that the number of residual malignant T cells predicted lesion recurrence. A retrospective review showed that early stage high-risk patients who received radiation as part of their treatment regimen had prolonged overall survival compared to patients who did not. Conclusions: These findings demonstrate that LDRT can eradicate malignant T cells in MF, provides robust disease control, and is associated with improved survival in high-risk early stage patients.