Abstract 3560: Adult T-cell leukemia/lymphoma in America: Unmasking a preventable cancer in Caribbean-born communities

Abstract Background: Adult T-cell leukemia/lymphoma (ATLL), caused by human T-lymphotropic virus type 1 (HTLV-1), is rare in the United States but endemic in the Caribbean, Japan, and West Africa. The burden of ATLL among Caribbean-born U.S. residents has not been quantified at the population level. Methods: We analyzed 2005-2022 data from the Cancer in North America (CiNA) registry to estimate ATLL incidence by race/ethnicity and nativity. Country-specific analyses were restricted to 13 states with <20% missing birthplace data. Sensitivity analyses addressed possible misclassification with peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). Cause-specific survival was assessed for Florida and New York using multivariable Cox regression and Kaplan-Meier methods. Results: ATLL incidence was several dozen-fold higher among non-Hispanic Caribbean-born adults compared with U.S./Canada-born populations, with rates in some Caribbean-origin groups approaching those reported in southwestern Japan. Nearly half of all U.S. ATLL cases occurred in New York and Florida, which had the highest national incidence. Within the Caribbean diaspora, risk varied widely by country of birth, with the highest rates in the eastern Caribbean, while Hispanic Caribbean-born populations exhibited lower incidence overall. Among more than one thousand patients from New York and Florida, five-year survival remained poor. Cutaneous and marrow-dominant forms showed better outcomes than nodal disease. After adjustment for age and sex, non-Hispanic Caribbean-born Black patients had roughly 2½-fold higher mortality than non-Hispanic White patients. Conclusions: ATLL among Caribbean-born U.S. populations represents one of the most concentrated yet preventable cancer disparities in the country. Because vertical HTLV-1 transmission drives lifetime risk, targeted surveillance, maternal screening, and culturally informed prevention programs are urgently warranted. These findings underscore the need for public-health recognition of ATLL as a preventable infection-associated malignancy in Caribbean-origin communities. Citation Format: Paulo S. Pinheiro, Amber N. Balda, Tabassum Z. Insaf, Baozhen Qiao, Sophia Hl George, Juan C. Ramos. Adult T-cell leukemia/lymphoma in America: Unmasking a preventable cancer in Caribbean-born communities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3560.