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

Unraveling the Prognostic Role of t(1:19) in Pediatric Pre-B Acute Lymphoblastic Leukemia: Insights from a Saudi Nationwide Cohort

Recurrent translocation t(1;19) (q23;p13) describes a unique cytogenetic group of childhood B-cell acute lymphoblastic leukemia (ALL). Historically, t(1;19)(q23;p13.3) has been associated with poor outcomes. However, recent data suggests that currently intensified treatments have overcome this dismal prognosis. We conducted this study to understand this type of translocation in our population. From January 1999 until May 2020, 44 children with t(1;19) were identified by cytogenetics analysis during charts review. Cytogenetics (CG) testing results (Karyotype and/or FISH) were retrieved from the medical files on 37/44 patients. Of the 37 patients with Cytogenetics results, a total of 12 patients were found to have t(1;19)(q23;p13.3) as the only detectable genetic change, 13 patients were presented with t(1;19)(q23;p13.3) plus further chromosomal rearrangement (Table 1), 12 patients were presented with a variation involving t(1;19)(q23;p13.3) with or without additional chromosomes rearrangement. Patients were treated on different protocols, yet most were derived from the North American guidelines. Among the included subjects, relapse or refractory disease was identified in 15 cases (34 %), and 12 died due to progressive refractory leukemia. At the five-year mark, the estimated overall survival rate stood at 72​​ %. No statistical difference existed between patients treated on the high-risk (HR) protocol and those treated on the standard-risk (SR) protocol. It appeared that t(1,19) standard risk ALL had more relapses on the standard risk protocol. Furthermore, Relapses were mostly earlier and poorly salvageable. As such, treatment intensification for standard risk ALL with t(1,19) is warranted.

Extended vincristine and dexamethasone pulse therapy may not be necessary for children with TCF3-PBX1 positive acute lymphoblastic leukaemia

The effect of prolonged pulse therapy with vincristine and dexamethasone (VD) during maintenance therapy on the outcome of paediatric patients with TCF3-PBX1 positive acute lymphoblastic leukaemia (ALL) remains uncertain. We conducted non-inferiority analysis of 263 newly diagnosed TCF3-PBX1 positive ALL children who were stratified and randomly assigned (1:1) to receive seven additional VD pulses (the control group) or not (the experimental group) in the CCCG-ALL-2015 clinical trial from January 2015 to December 2019 (ChiCTR-IPR-14005706). There was no significant difference in baseline characteristics between the two groups. With a median follow-up of 4.2 years, the 5-year event-free survival (EFS) and 5-year overall survival (OS) in the control group were 90.1% (95% confidence interval [CI] 85.1-95.4) and 94.7% (95% CI, 90.9-98.6) comparable to those in the experimental group 89.2% (95% CI 84.1-94.7) and 95.6% (95% CI 91.8-99.6), respectively. Non-inferiority was established as a one-sided 95% upper confidence bound for the difference in probability of 5-year EFS was 0.003, and that for 5-year OS was 0.01 by as-treated analysis. Thus, omission of pulse therapy with VD beyond one year of treatment did not affect the outcome of children with TCF3-PBX1 positive ALL.

Outcomes of Adolescent Patients with Acute Lymphoblastic Leukemia: Long-term Follow-up of 335 Patients

BACKGROUND

Adolescents (aged 10-17 years) with acute lymphoblastic leukemia (ALL) represent a unique patient population, with a disproportionate survival disadvantage compared with younger patients. We aimed to determine the outcomes and prognostic factors of adolescent patients treated at our institution.

PATIENTS AND METHODS

Between 2005 and 2017, 335 adolescents with ALL were enrolled; clinical characteristics and treatment outcomes were analyzed and compared between adolescents and younger children (1-9 years old, n = 704).

RESULTS

Adolescents were more likely to have high-risk factors such as hyperleukocytosis, a T-cell immunophenotype, BCR-ABL1, and/or poor early treatment responses. Compared with younger children, adolescents had significantly worse 5-year event-free survival (EFS) (73.0% ± 2.5% vs. 82.6% ± 1.5%; P < .001) and overall survival (OS) (77.1% ± 2.3% vs. 87.7% ± 1.3%; P < .001). Furthermore, younger adolescents (10-14 years) tended to have better outcomes compared with those older than 15 years (5-year OS: 79.3% ± 2.5% vs. 68.4% ± 5.7%; P = .042), mainly because of the lower frequencies of toxicities. On multivariate analysis, white blood count ≥ 50 × 10⁹/L and extramedullary involvement at diagnosis were the most powerful prognostic factors for both OS and EFS.

CONCLUSION

The outcomes among adolescent patients were not as good as that of younger children. Further studies are required to define optimal treatment strategies for adolescents, particularly those aged 15 to 17 years.