Anaplastic Large Cell Lymphoma of the Breast by Race and Ethnicity.

Importance: The incidence rate of primary breast anaplastic large cell lymphoma (ALCL), a complication associated with breast implants, is rapidly rising in the US. Comprehensive studies on the racial and ethnic epidemiologic characteristics of ALCL in the US are lacking, despite evidence of worldwide geographic variability. Objective: To characterize the incidence rates of breast ALCL by race and ethnicity in the US. Design, Setting, and Participants: This retrospective, observational, population-based cohort study obtained data from the Surveillance, Epidemiology, and End Results program database. The cohort comprised women who were newly diagnosed with primary ALCL within the breast between January 1, 2000, and December 31, 2020. Data analysis was conducted from March to June 2024. Exposure: Patient race and ethnicity. Main Outcomes and Measures: Age-adjusted incidence rate of breast ALCL per 100 million persons per year. Results: In a cohort of 868 118 334 women at risk of breast ALCL over 943 941 114 person-years from 2000 to 2020, 90 were diagnosed with breast ALCL and 55 were diagnosed with T-cell lymphoma, not otherwise specified, resulting in 145 women in the combined (breast ALCL plus T-cell lymphoma, not otherwise specified) cohort. The mean (SD) age of this cohort was 57.6 (15.9) years. These patients self-reported as Hispanic (19 [13.1%]) and non-Hispanic American Indian or Alaska Native (<11 [<7.6%]), Asian or Pacific Islander (<11 [<7.6%]), Black (<11 [<7.6%]), and White (105 [72.4%]). The overall incidence rate of breast ALCL was 9.7 (95% CI, 7.7-11.9) per 100 million persons per year. Incidence rates per 100 million persons per year were highest for White (11.6; 95% CI, 9.0-14.9), followed by Hispanic (7.5; 95% CI, 4.0-13.0), Black (3.5; 95% CI, 0.7-10.1), and Asian or Pacific Islander (0.9; 95% CI, 0.0-5.7) patients. From 2000 to 2010 through 2011 to 2020, incidence rates per 100 million persons per year of breast ALCL increased for Hispanic (0.8 [95% CI, 0.0-7.1] to 12.7 [95% CI, 6.5-22.3]) and White patients (3.9 [95% CI, 2.0-6.9] to 20.1 [95% CI, 15.0-26.5]), but no increase was observed for Black patients (4.9 [95% CI, 0.5-17.4] to 2.4 [95% CI, 0.0-12.5]). Similar patterns were observed in a sensitivity analysis incorporating additional cases of T-cell lymphoma, not otherwise specified, to capture upper estimates of incidence rates. Conclusions and Relevance: In this cohort study, incidence rates of breast ALCL were highest and increased most rapidly in Hispanic and non-Hispanic White patient populations, while only a few cases were reported in American Indian or Alaska Native, Asian or Pacific Islander, and Black populations. Future studies should delineate the factors associated with these differences and continue to monitor textured breast implant utilization.