Allogeneic stem cell transplant for treatment of mycosis fungoides and Sezary syndrome: a systematic review and meta-analysis

Allogeneic hematopoietic stem cell transplant (allo-HSCT) has been noted to be a potential curative treatment in cases of advanced-stage mycosis fungoides (MF) or Sezary syndrome (SS). To assess outcomes of allo-HSCT for MF/SS we performed a systematic review and meta-analysis including 15 manuscripts and 557 patients, published from 2010–2023. Meta-analysis revealed 1-year and 3+year overall survival (OS) of 51% (95% CI 39–64%) and 40% (32–49%). Progression-free survival at 1 year and 3+years were 42% (31–53%) and 33% (25–42%). Non-relapse mortality was 18% (13–23%). Relapse occurred in of 47% (40–53%) with a median time to relapse of 7.9 months (range 1.6–24 months). Rates of acute and chronic graft-versus-host disease (GVHD) were 45% (35–55%) and 40% (33–48%). Reduced-intensity conditioning (RIC) was associated with superior OS compared to myeloablative conditioning (MAC) (58% vs. 30%, p < 0.001). Of patients with relapse after allo-HSCT, 46% treated with donor lymphocyte infusion (DLI) achieved complete remission. These data support use of allo-HSCT for treatment of advanced-stage MF/SS and suggest superiority of RIC over MAC. Rates of GVHD were comparable to allo-HSCT in general. The improved OS for RIC and high rate of CR with DLI underscore the importance of the graft-versus-lymphoma effect in allo-HSCT for MF/SS.