Efficacy of Allogeneic Hematopoietic Cell Transplantation in Cutaneous T Cell Lymphoma: Results of a Systematic Review and Meta-Analysis.

Mycosis fungoides and Sézary syndrome are the most common types of primary cutaneous T cell lymphomas. The clinical presentation of mycosis fungoides is generally indolent, whereas Sézary syndrome represents a more aggressive disease variant. Stage at diagnosis is the most important determinant of long-term survival outcome. Although most patients present with early-stage disease, those who develop progressive disease or have an advanced stage represent a therapeutic challenge because of a lack of effective therapies. Allogeneic hematopoietic cell transplantation (allo-HCT) has been used as a potentially curative treatment modality with encouraging long-term outcomes. However, a lack of randomized controlled data remains, and the published literature is limited to mostly retrospective studies. We performed a comprehensive search of the medical literature using PubMed/Medline, EMBASE, and Cochrane reviews on September 13, 2018. We extracted data on clinical outcomes related to benefits (overall [OS] and progression-free [PFS] survival) and harms (relapse and nonrelapse mortality [NRM]) independently by 2 authors. Our search strategy identified 289 references. Five studies (266 patients) were included in this systematic review and meta-analysis. Reduced-intensity and nonmyeloablative regimens were more commonly prescribed (76%). Mobilized peripheral blood stem cells were the preferred graft source (78%). The pooled OS and PFS rates were 59% (95% confidence interval [CI], 50% to 69%) and 36% (95% CI, 27% to 45%), respectively. Pooled relapse rate was 47% (95% CI, 41% to 53%) and pooled NRM rate 19% (95% CI, 13% to 27%). Results of this systematic review and meta-analysis show that allo-HCT yields encouraging OS and PFS rates; however; relapse remains a significant cause of allo-HCT failure. Novel strategies to further improve outcomes should focus on offering allo-HCT before the development of resistant disease and reducing relapse by incorporating post-transplant maintenance therapies.