Minimal residual disease level determined by flow cytometry provides reliable risk stratification in adults with T-cell acute lymphoblastic leukaemia

Minimal residual disease (MRD) is an important independent prognostic factor for relapse and survival in acute lymphoblastic leukaemia (ALL). Compared with adult B-cell ALL, reports of adult T-cell ALL (T-ALL) MRD have been scarce and mostly based on molecular methods. We evaluated the prognostic value of multiparameter flow cytometry (FCM)-based MRD at the end of induction (EOI-MRD). The present retrospective study included 94 adult patients with T-ALL. MRD was detected by six- to eight-colour FCM. Patients who were EOI-MRD positive had a higher cumulative incidence of relapse (CIR) (87 center dot 6% vs. 38 center dot 8%, P = 0 center dot 0020), and a lower relapse-free survival (RFS) (5 center dot 4% vs. 61 center dot 0%, P = 0 center dot 0005) and overall survival (OS) (32 center dot 7% vs. 69 center dot 7%, P < 0 center dot 0001) than those who were EOI-MRD negative. Moreover, for patients who received allogeneic haematopoietic stem cell transplantation (allo-HSCT) at their first remission, EOI-MRD positivity was predictive of post-transplant relapse (2-year CIR: 68 center dot 2% vs. 4 center dot 0%, P = 0 center dot 0003). Multivariate analysis showed that EOI-MRD was an independent prognostic factor for CIR [hazard ratio (HR) 2 center dot 139, P = 0 center dot 046], RFS (HR 2 center dot 125, P = 0 center dot 048) and OS (HR 2 center dot 987, P = 0 center dot 017). In conclusion, EOI-MRD based on FCM was an independent prognostic factor for relapse and survival in adult T-ALL. For patients who underwent HSCT, EOI-MRD could be used to identify patients with a high risk of relapse after allo-HSCT.

Automated summary

In adult T-cell acute lymphoblastic leukemia (T-ALL) patients, inductions end-stage MRD based on FCM is an independent prognostic factor for relapse and survival. EOI-MRD positivity can predict post-transplant relapse in patients undergoing allo-HSCT for the first remission.