Real-world survival analysis of adolescent and young adult patients with hairy cell leukemia in the United States.

Abstract

e19031 Background: Hairy cell leukemia (HCL) is a rare indolent B-cell malignancy with favorable outcomes. Adolescents and young adults (AYA; ages 15–39) are underrepresented in population-based studies, and factors influencing outcomes in this group remain poorly defined. We evaluated survival and associated predictors among AYA patients with HCL in the United States using the National Cancer Database (NCDB). Methods: In this IRB approved retrospective analysis, AYA patients diagnosed with HCL between 2004–2023 were identified from the NCDB. Survival was estimated using Kaplan–Meier methods. Cox proportional hazards regression was used to evaluate predictors of mortality. Multivariable models included demographic characteristics, insurance status, Charlson–Deyo comorbidity score, treatment variables, and year of diagnosis. Subgroup analyses were performed among patients diagnosed from 2013–2023, reflecting the era in which rituximab was coded as immunotherapy. Results: Among 906 AYA patients identified, 850 had available vital status. A total of 37 deaths (4.4%) were observed, corresponding to approximately 96% survival at last follow-up. The cohort was predominantly male (77.3%) and White (91.5%), with most patients having Charlson–Deyo score 0. Higher comorbidity burden was associated with worse survival but the survival did not differ by receipt of systemic therapy versus no treatment recorded, or by time from diagnosis to treatment initiation (≤60 vs >60 days). In multivariable analysis, insurance status was the strongest independent predictor of mortality; uninsured (HR 5.99, 95% CI 2.63–13.65; p<0.001) and governmental insured patients (HR 3.03, 95% CI 1.37–6.73; p=0.006) had higher mortality compared with privately insured patients. Diagnosis during 2004–2013 was independently associated with lower mortality compared with 2013–2023 (HR 0.34, 95% CI 0.15–0.74; p=0.0066). In the 2013–2023 subgroup (n=471; 25 deaths), insurance status remained the only independent predictor of mortality. Immunotherapy was not associated with survival differences. Multi-agent chemotherapy was associated with worse survival compared with single-agent therapy in unadjusted analyses. Conclusions: AYA patients with HCL in the United States experience excellent population-level survival, with a low observed frequency of multiple primary malignancies. Despite this favorable prognosis, comorbidity burden and significant insurance-based disparities remain clinically relevant, underscoring the importance of equitable access to care and long-term follow-up. Baseline characteristics of AYA patients with HCL. Characteristic n (%) Male sex 657 (77.3) White race 764 (91.5) Charlson–Deyo score ≥1 50 (5.9) Private insurance 632 (76.1) Government insurance 130 (15.6) Uninsured 69 (8.3) Time to systemic therapy ≤60 days 657 (89.3) Any treatment received 538 (92.3)