Long-Term Results of the Risk-Stratified Treatment of TCF3-PBX1–Positive Pediatric Acute Lymphoblastic Leukemia in China

Abstract

BackgroundAcute lymphoblastic leukemia (ALL) with t(1;19)/TCF3-PBX1 is a common genotype, and its prognosis has significantly improved owing to risk stratification and intensive treatment. This study aimed to determine the outcomes and prognostic factors of patients with TCF3-PBX1 treated with the modified Berlin-Frankfurt-Münster protocol. Patients and MethodsBetween 2005 and 2017, a total of 1051 pediatric patients with ALL were enrolled. TCF3-PBX1 was detected by reverse-transcriptase PCR and/or cytogenetic analysis. Clinical characteristics and treatment outcomes were analyzed and compared in patients with TCF3-PBX1 and with other B-precursor ALL (B-ALL). ResultsTCF3-PBX1 was detected in 64 patients with ALL (6.1%), and all were of B-cell lineage. These patients were more likely to express the pre–B-ALL immunophenotype (P < .001), be in the National Cancer Institute high-risk group (P = .030), and exhibit more rapid disease clearance during induction therapy (P < .001) compared to patients with other B-ALL. However, the outcomes of this genotype were not better than those of other patients with intermediate risk. At a median (range) follow-up of 60.6 (0.8-184.5) months, the estimated 5-year overall survival was 85.2 ± 4.6% versus 88.2 ± 1.8% (P = .500) and 5-year event-free survival was 76.8 ± 5.5% versus 83.0 ± 2.0% (P = .210) for patients with TCF3-PBX1 and those with other B-ALL. After adjusting for other risk factors, reemergent minimal residual disease (MRD) was the most significant poor prognostic indicator for patients with TCF3-PBX1. ConclusionThe overall outcome of patients with TCF3-PBX1 was intermediate at our institution. Sequential MRD measurement is important for this genotype. Thus, more efforts should be made to eradicate reemergent MRD to improve prognosis.