2.1 Patients and chemotherapeutic regimens
We searched the Sun Yat-sen University Cancer Center (SYSUCC) database. The inclusion criteria were: (1) aged ≤ 18 years; (2) newly diagnosed as the four main categories of NHL between 2014 and 2020; (3) treated according to the modified BFM95 protocol. At diagnosis, patients were staged using the new International Pediatric NHL Staging System (IPNHLSS).25 Based on the clinicopathological features, including stage, surgical outcomes before chemotherapy, LDH (lactate dehydrogenase) levels, pathological subtype and involved organs, patients with BL/DLBCL and ALCL were stratified into four risk groups: very low, low, intermediate, and high; patients with LBL were stratified into low-, intermediate- and high-risk groups according to their stage, genotype, immunophenotyped, and response to induction therapy. This study was approved by the SYSUCC Institutional Review Board and the Research Ethics Committee (IRB: B2020-160-01).