Racial Patterns of Peripheral T-Cell Lymphoma Incidence and Survival in the United States

Abstract

Purpose: To compare incidence and survival of peripheral T-cell lymphoma (PTCL) subtypes among US racial/ethnic groups.

Methods: Patients with PTCL (age ≥ 15 years; 2000 to 2012) were identified in the Surveillance, Epidemiology, and End Results (SEER) registries. Race/ethnicity was categorized as non-Hispanic white, black, Asian/Pacific Islander, Hispanic white, or American Indian/Alaskan native. Age-standardized annual incidence rates and incidence rate ratios were estimated with 95% CIs, and case-case odds ratios were estimated by race/ethnicity using polytomous regression. Survival was estimated from SEER follow-up data with Cox regression.

Results: Thirteen thousand one hundred seven patients with PTCL were identified. Annual PTCL incidence was highest in blacks and lowest in Native Americans. Compared with non-Hispanic whites, blacks had a higher incidence of PTCL not otherwise specified (PTCL-NOS), anaplastic large-cell lymphoma, and adult T-cell leukemia/lymphoma (ATLL) and a lower incidence of angioimmunoblastic T-cell lymphoma (AITL); Asians/Pacific Islanders had a higher incidence of AITL, extranodal nasal-type natural killer/T-cell lymphoma and NK-cell leukemia (ENKCL), and ATLL and a lower incidence of anaplastic large-cell lymphoma; Hispanics had a higher incidence of AITL and ENKCL; and Native Americans had a lower incidence of PTCL-NOS (all P < .05). The ratio of ENKCL to PCTL-NOS among Native Americans, Asians/Pacific Islanders, and Hispanic whites was approximately three- to four-fold the same ratio among non-Hispanic whites. Survival varied significantly by race/ethnicity (P < .001), with blacks in particular experiencing shorter survival for most subtypes.

Conclusion: Striking variation in incidence, proportions of PTCL subtypes, and survival was observed. Aspects of these PTCL subtype patterns, such as for ENKCL and ATLL, were similar to corresponding global populations. Despite the small population size and limited number of Native American patients, PTCL subtype frequencies in this group were distinct but most similar to Hispanic whites. Survival disparities were evident, especially for blacks compared with non-Hispanic whites.

Fig 1.

Incidence rate ratios (IRRs) of peripheral T-cell lymphoma (PTCL) subtypes by race/ethnicity compared with non-Hispanic whites (NHWs) in US Surveillance, Epidemiology, and End Results cancer registries (2000 to 2012). IRRs were calculated from age-standardized incidence rates. AI/AN, American Indian/Alaskan native; AITL, angioimmunoblastic T-cell lymphoma; ALCL, anaplastic large-cell lymphoma; A/PI, Asian/Pacific Islander; ATLL, adult T-cell lymphoma/leukemia; ENKCL, extranodal nasal-type natural killer (NK)/T-cell lymphoma and NK-cell leukemia; HW, Hispanic white; ND, not determined because of small numbers; PTCL-NOS, PTCL not otherwise specified.

Fig 2.

Overall survival of patients with peripheral T-cell lymphoma (PTCL) according to subtype and race/ethnicity, from US Surveillance, Epidemiology, and End Results cancer registries (2000 to 2012). P values are from global log-rank tests of the survival curves. AI/AN, American Indian/Alaskan native; AITL, angioimmunoblastic T-cell lymphoma; ALCL, anaplastic large-cell lymphoma; A/PI, Asian/Pacific Islander; ATLL, adult T-cell lymphoma/leukemia; ENKCL, extranodal nasal-type natural killer (NK)/T-cell lymphoma and NK-cell leukemia; HW, Hispanic white; NHW, non-Hispanic white; PTCL-NOS, PTCL not otherwise specified.