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

Abstract

BackgroundAdolescents (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 MethodsBetween 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). ResultsAdolescents 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. ConclusionThe 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.