Treatment response

Prednisone treatment is beneficial to risk stratification and prognosis evaluation of ALL patients. ① Prednisone response (PR): those with absolute peripheral blood naive lymphocyte count < 1000 × 10⁶/L on Day 8 of prednisone induction were considered prednisone good responders (PGR), while those ≥1000 × 10⁶/L were considered prednisone poor responders (PPR); ② Morphological evaluation of bone marrow smear was performed on Day-15 and Day-33. Patients were classified according to their blast cells amount, with M1 (blast cells< 5%), M2 (5% to< 25%), or M3 (> 25%); (3) Relapse: including BM relapse, central nervous system (CNS) relapse, testicular relapse and combined relapse.BM relapse means that after complete remission (CR) of ALL, the ratio of primitive plus naive cells in bone marrow is > 25% on review. CNS relapse means that primitive plus naive cells are detected in cerebrospinal fluid by centrifugal smear or CNS infiltration is present and other causes cannot be explained or CT/MRI showed brain or meningeal lesions, testicular relapse i.e. ultrasound or biopsy confirmed unilateral or bilateral testicular leukemic cell infiltration, combined relapse i.e. extramedullary relapse (central and/or testicular relapse) with > 5% leukemic cells in the BM; ④ Events included: persistent non-CR, relapse, development of a second tumor, death and so on.