Chronic lymphocytic leukemia/small lymphocytic lymphoma nationwide analysis: Comparing sociodemographic and survival outcomes among Hispanics and non-Hispanics in the United States.

Abstract

e19505 Background: In essence, chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are the same , CLL being the most common leukemia in Western countries. (Blood PMID 29540348, CA Cancer J Clin PMID 35020204) Survival outcomes in CLL/SLL among Hispanics (HI) and Non-Hispanics (NH) have been controversial. (Cancer Causes Control PMID 34677741, Cold Spring Harb Mol Case Stud PMID 33593728) This analysis attempts to clarify if sociodemographic characteristics influence survival of HI diagnosed with CLL/SLL in the United States (US). Methods: Retrospective data analysis on CLL/SLL patients in the US reported to the Surveillance, Epidemiology, and End Results (SEER) 18 database from 2000-2018. Demographics, disease characteristics, and survival patterns were analyzed across ethnic groups, HI vs NH. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS). Multivariate analysis and propensity score matching was performed, adjusting for age, stage, and B-symptoms. Results: 98884 CLL/SLL patients were included, 5012 HI. Males predominated in both HI and NH. HI compared to NH, were diagnosed at a younger median age, 68 years vs 70 years, respectively [p<0.001]. Majority of patients belonged to the age bracket of 60-80 years; favoring a younger age distribution in HI. Most patients were white, and NH had greater heterogeneity [p<0.001]. Unknown stage at diagnosis followed by advance stage (III/IV) prevailed for both ethnicities [p=0.075]. B-symptoms were mostly unknown in both groups. The tendency was towards not receiving radiation as part of the treatment. Survival probability at 2, 5 and 10 years for HI (0.829, 0.677, and 0.474) was similar compared to NH (0.831, 0.664 and 0.437), respectively. The median survival time was 9.3 years for HI vs 8.5 years for NH, with a statistically significant difference in OS favoring HI [p=0.0045] On multivariate analysis, patients older than 80 years and between 60-80, had worse OS than those less than 60, with hazard ratio (HR) 7.5 [95% CI: 7 – 8.1] and 2.5 [95% CI: 2.4-2.7], respectively. Also, stage III and IV, had inferior OS than those at early stages, with HR 1.4 [95% CI: 1.1 – 1.6] and HR 1.2 [95% CI: 1 – 1.4], respectively. Conclusions: In this analysis, HI with CLL/SLL have a superior OS, which was noted to be statistically significant. Also, multivariate analysis showed correlation of better OS when CLL/SLL was identified at a younger age and early stages. Although demographic differences may be driving the survival effect in HI as they were noted to be younger; identification and better understanding of intrinsic disease characteristics, treatment patterns, and biological variables; may aid in the understanding on how these factors contribute and impact the survival advantage in this ethnic group.