Indication and benefit of upfront hematopoietic stem cell transplantation for T-cell lymphoblastic lymphoma in the era of ALL-type induction therapies

Abstract

Since the introduction of leukemia-type induction therapies for T-cell lymphoblastic lymphoma (T-LBL), improvements in the long-term outcomes of T-LBL have been reported. However, indications for and the appropriate timing of hematopoietic stem cell transplantation (HSCT) have not yet been established. Therefore, we performed a multicenter retrospective cohort study of patients with T-LBL treated using leukemia-type initial therapies to compare the outcomes after HSCT at different disease stages. We enrolled 21 patients with T-LBL from a total of 11 centers, and all patients received hyper-CVAD as a leukemia-type initial regimen. HSCT was performed during the CR1/PR1 (standard disease) stage in 11 patients, while it was completed at a later or non-remission (advanced disease) stage in 10 patients. Following HSCT, the overall survival rate was significantly greater in standard disease than in advanced-disease patients (79.5% vs. 30.0% at 5 years; hazard ratio (HR) 5.97; p = 0.03), with trend to the lower incidence of relapse in the former group (27.3% vs. 60.0% at 5 years; HR 2.29; p = 0.19). A prognostic difference was not detected between cases treated with allogeneic and autologous HSCTs. Our study suggests that frontline HSCT may be a feasible treatment option for T-LBL, even in the era of leukemia-type initial therapy.

Figure 1

Schematic workflow of patients and the pre-HSCT clinical course. Summary of treatment response from diagnosis to HSCT. Upfront HSCT at CR1/PR1 was categorized as standard disease, while HSCT performed in the other status was classified as advanced disease.

Figure 2

Prognosis after HSCT in the whole cohort. (A) Overall survival after HSCT was calculated using the Kaplan–Meier method. (B) Non-relapse mortality is shown treating relapse as a competing risk. (C) The cumulative incidence of relapse was calculated treating death without relapse as a competing risk.

Figure 3

Comparison of post-HSCT prognosis according to the disease risk at HSCT. Comparison of prognosis between standard disease (HSCT at CR1/PR1) and advanced disease (HSCT at CR2/PR2 or at non-remission status) regarding (A) overall survival, (B) non-relapse mortality, and (C) relapse.

Figure 4

Overall survival after the initial diagnosis of T-LBL. (A) Overall survival after the time of initial diagnosis is shown, and (B) compared between standard- and advanced-disease patients.