OBJECTIVETo study the clinical features of children with relapsed acute lymphoblastic leukemia (ALL) treated with the CCLG-ALL2008 protocol.

METHODSThe data of 591 children who were newly diagnosed with ALL and were treated with the CCLG-ALL 2008 protocol between April 2008 and June 2013 were collected, and the clinical features of 80 children with relapsed ALL were retrospectively analyzed.

RESULTSAfter treatment with the CCLG-ALL2008 protocol, the recurrence rate in the standard-risk, intermediate-risk and the high-risk groups were 7.0%, 10.7% and 28.7% respectively (P<0.05). The recurrence rate in patients with TEL/AML1-positive ALL was 8.0%, and the 5-year overall survival (OS) of the relapsed patients was 37.04%. The recurrence rates in patients with MLL-positive and BCR/ABL-positive ALL were 35.0% and 24.2% respectively, and none of the relapsed patients had long-term survival. The recurrence mainly occurred at the very early stage (53%), and none of patients with recurrence at the very early stage had long-term survival. The recurrence occurred at early stage and late stage accounted for 34% and 14% respectively, and the 5-year OS rates of patients with recurrence at early stage and late stage were 11.44% and 60.00% respectively. The sites of recurrence were mainly bone marrow alone (83%), and the 5-year OS of patients with recurrence at bone marrow alone was 9.23%. The recurrence in bone marrow and outside bone marrow accounted for 11%, and the 5-year OS of patients with recurrence in both bone marrow and outside bone marrow was 25.00%. The recurrence only outside bone marrow accounted for 6%, and the 5-year OS of patients with recurrence only outside bone marrow was 100%. The recurrence rate in patients with T-cell ALL was 9.5%, and none of the relapsed patients had long-term survival. The recurrence rate in patients with B-cell ALL was 14.3%, and the 5-year OS of the relapsed patients was 15.52%.

CONCLUSIONSAfter treatment with the CCLG-ALL2008 protocol, a relatively high recurrence rate is observed in children with high-risk ALL. Positive MLL and positive BCR/ABL are high-risk factors for recurrence. The recurrence rate is not significantly correlated with immunophenotype. A very low survival rate is seen in children whose recurrence have the following features: at early stage, only in bone marrow, T-cell ALL, and abnormal BCR/ABL and MLL.