Outcomes of allogeneic hematopoietic stem cell transplantation versus intensive chemotherapy in patients with myeloid sarcoma: a nationwide representative multicenter study.

Myeloid sarcoma (MS) is a rare hematological neoplasm with poor prognosis, posing a significant clinical challenge due to the absence of effective and standardized treatments. We conducted a retrospective analysis of 162 MS patients treated at 12 centers to compare outcomes between intensive chemotherapy and allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our analysis revealed that allo-HSCT demonstrated superior overall survival (OS) within the initial 36 months compared to intensive chemotherapy alone (p = 0.037). However, beyond 36 months (36-60 months), a reverse trend was observed (p = 0.056). Subgroup analysis revealed potential benefit for isolated MS patients with allo-HSCT, but not for those with leukemic MS. Additionally, in patients achieving first complete remission (CR1) after induction chemotherapy, allo-HSCT did not significantly improve 5-year OS compared with intensive chemotherapy alone (p = 0.25). Conversely, allo-HSCT significantly improved 5-year OS in non-CR1 patients (p < 0.001). Notably, HLA-matched HSCT and haploidentical HSCT showed comparable outcomes in terms of OS, disease-free survival, and cumulative incidence of relapse. In conclusion, allo-HSCT improved outcomes for MS patients within 36 months of disease onset, and haploidentical HSCT emerged as a viable treatment option for patients without matched donors.