Impact of Age and Race on Survival in Adult T-Cell Leukemia/Lymphoma in the United States

Introduction

Adult T-cell leukemia/lymphoma (ATLL) is a T-cell neoplasm that has been shown to be associated with human T-cell leukemia virus-1 (HTLV-1) (Gallo RC; et al. The Global Virus Network's Task Force on HTLV-1; Screening transplant donors for HTLV-1 and -2. Blood 2016; 128 (26): 3029-3031.). Though it is a less common hematologic malignancy, there is an increasing incidence in certain populations in the United States (Shah UA, et al. Epidemiology and survival trend of adult T-cell leukemia/lymphoma in the United States. Cancer 2020, 126:567-574.). The survival trends in different demographic groups in the United States are not well documented and are worth exploring in this aggressive disease.

Methods

Source data is from the Surveillance, Epidemiology, and End Results (SEER) 18 registry which included 606 individuals with ATLL and their demographic information, survival in months, and status. Demographic data included in this analysis was age divided into quartiles (47 years and younger, 48-60 years, 61-74 years, 75 years and older), sex, race (Non-Hispanic White, Non-Hispanic Black, Hispanic, Non-Hispanic Asian or Pacific Islander, Non-Hispanic American Indian/Alaska Native, and Non-Hispanic Unknown Race), region (Midwest [IA], Northeast [CT, NJ], South [GA, KY, LA], and West [AK, CA, HI, NM, UT, WA]), and year of diagnosis in ranges (2000-2004, 2005-2009, 2010-2014, 2015-2020). Status was dichotomized to alive and deceased by any cause. A Cox proportional hazards model was used to evaluate the association of survival time and status with predictor variables sex, age, race, and year of diagnosis.

Result

Analysis reveals significant associations between survival and age. Compared to the reference group of the first age quartile (47 years and younger), all other quartiles had significantly worse survival: 48-60 years (hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.12-1.99, p-value 0.007), 61-74 years (HR 2.00, 95% CI 1.50-2.67, p-value <0.001), and 75 years and older (HR 3.28, 95% CI 2.44-4.42, p-value <0.001). There were also significantly worse outcomes for some races compared to reference Non-Hispanic White: Non-Hispanic Black (HR 2.04, 95% CI 1.61-2.60, p-value <0.001) and Non-Hispanic Asian or Pacific Islander (HR 1.62, 95% CI 1.19-2.20, p-value 0.002). Other races did not have significant differences in survival. Sex and year of diagnosis were not significantly associated with the outcome.

Conclusions

This analysis offers an updated insight into this rare malignancy and the impact it has upon different populations in the United States. The significantly worse survival of those in older age quartiles and Non-Hispanic Black and Non-Hispanic Asian or Pacific Islander warrants further investigation and evaluation, especially in populations not included in this SEER18 registry. This data did not include information from New York State, which has been shown to have the highest rate of ATLL cases in the nation and an increasing incidence of ATLL (Shah UA, et al.). Outcomes progressively worsen as a person enters older age groups, a trend which should be explored regarding prognostication and treatment. That there are significant associations between survival and Non-Hispanic Black and Non-Hispanic Asian or Pacific Islander races is also important as these populations have been found to have a higher prevalence of HTLV-1 and greater incidence of ATLL in the United States (Adams SV, et al. Racial Patterns of Peripheral T-Cell Lymphoma Incidence and Survival in the United States. J Clin Oncol 2016, Mar 20;34(9):963-71.). Furthermore, the disproportionate effect on older and Non-Hispanic Black Americans, groups that have been traditionally marginalized, is one that should not be ignored but investigated further.

Janakiram:JANNSEN: Honoraria, Research Funding; LEGEND: Honoraria, Research Funding; BMS: Honoraria, Research Funding; FATE THERAPEUTICS: Research Funding. Shastri:NACE & PeerView: Honoraria; Jassen: Consultancy; Gilead, Rigel, Kymera: Consultancy; Kymera: Research Funding; Ryvu therapeutics: Research Funding; Geron: Speakers Bureau.