Prognostic factors of childhood acute lymphoblastic leukemia with TCF3-PBX1 in CCCG-ALL-2015: a multi-center study

Abstract To identify prognostic factors that can be used to further improve outcome, we studied 384 patients with this genotype treated on Chinese Children’s Cancer Group acute lymphoblastic leukemia (ALL) -2015 protocol between 1 January 2015 and 31 December 2019. All patients provisionally received intensified chemotherapy in the intermediate-risk. The overall 5-year event-free survival (EFS) was 84.4% (95% confidence interval [CI], 80.6-88.3). Independent factors associated with lower 5-year EFS were male sex (80.4%, [95% CI, 74.8-86.4] vs. 88.9%, [95% CI, 84.1-93.9] in female, p = 0.033) and positive Day 46 minimal residual disease (MRD) (≥ 0.01%) (62.1%, [95% CI, 44.2-87.4] vs. 87.1%, [95% CI, 83.4-90.9] in patients with negative MRD, p < 0.001). The presence of testicular leukemia at diagnosis (n=10) was associated with particularly poorer 5-year EFS (33.3% [95% CI, 11.6-96.1] vs. 83.0% [95% CI, 77.5-88.9] in the other 192 male patients, P < 0.001) and was an independent risk factor (HR, 5.7, [95% CI, 2.2-14.5], p < 0.001). These data suggest that the presence of positive MRD after intensive remission induction and testicular leukemia at diagnosis are indications for new molecular therapeutics or immunotherapy in patients with TCF3-PBX1 ALL.