Allogeneic stem cell transplantation for advanced cutaneous T-cell lymphomas: a study from the French Society of Bone Marrow Transplantation and French Study Group on Cutaneous Lymphomas

The treatment of advanced stage primary cutaneous T-cell lymphomas remains challenging. In particular, large-cell transformation of mycosis fungoides is associated with a median overall survival of two years for all stages taken together. Little is known regarding allogeneic hematopoietic stem cell transplantation in this context. We performed a multicenter retrospective analysis of 37 cases of advanced stage primary cutaneous T-cell lymphomas treated with allogeneic stem cell transplantation, including 20 (54%) transformed mycosis fungoides. Twenty-four patients (65%) had stage IV disease (for mycosis fungoides and Sézary syndrome) or disseminated nodal or visceral involvement (for non-epidermotropic primary cutaneous T-cell lymphomas). After a median follow up of 29 months, 19 patients experienced a relapse, leading to a 2-year cumulative incidence of relapse of 56% (95%CI: 0.38–0.74). Estimated 2-year overall survival was 57% (95%CI: 0.41–0.77) and progression-free survival 31% (95%CI: 0.19–0.53). Six of 19 patients with a post-transplant relapse achieved a subsequent complete remission after salvage therapy, with a median duration of 41 months. A weak residual tumor burden before transplantation was associated with increased progression-free survival (HR=0.3, 95%CI: 0.1–0.8; P=0.01). The use of antithymocyte globulin significantly reduced progression-free survival (HR=2.9, 95%CI: 1.3–6.2; P=0.01) but also transplant-related mortality (HR=10−7, 95%CI: 4.10−8−2.10−7; P