Epidemiology of Breast Implant-Associated Anaplastic Large Cell Lymphoma - A systematic review of literature.

[INTRODUCTION] Breast Implant Associated - Anaplastic Large Cell Lymphoma (BIA-ALCL) cases are steadily increasing worldwide. When considering only the patients with textured implant as the active population, prevalence appears higher than previously reported, and uncertainty regarding incidence rate (IR) trends. We aimed to provide comprehensive estimates by identifying epidemiologic studies reporting prevalence, risk, and IR.

[METHODS] A systematic review was conducted up to November 2024 across PubMed, Google Scholar, and Web of Science. Epidemiological data were extracted from the "Patient Registry and Outcomes for Breast Implants and Anaplastic Large Cell Lymphoma Etiology and Epidemiology" (PROFILE) registry (US-specific), Food and Drug Administration (FDA)-Medical Device Reporting (MDR) (US/global), and BIA-ALCL Global Network (worldwide), providing granular data for 2019-2024, enabling yearly IR analysis. All findings were normalized using textured implants patients as the denominator. Interrupted time-series analysis was used to determine the impact of the COVID-19 pandemic on BIA-ALCL reporting.

[RESULTS] Among the 1949 studies, 23 were analyzed.

[PREVALENCE] 1.0-397.9/100,000 persons; risk: 1:250-1:99,992; and IR 0.021-124/100.000 persons/year. Nationally (US), PROFILE and FDA-MDR data showed IR peaking in 2020 (16.4 and 25.7/100,000) and then declining. Globally, FDA-MDR estimates peaked in 2021 (0.95/100,000) and plummeted in 2022 (0.14/100,000). Global Network data peaked in 2018 (0.68/100,000), dropped in 2020 (0.18/100,000), but rose again in 2024 (0.73/100,000). Significant IR declines (p = 0.02), were identified during the COVID-19 pandemic (2020-2022). Global data suggest transient underreporting and diagnostic delays.

[CONCLUSION] BIA-ALCL IR decreased in 2022, then rose globally in 2023-2024, but not in the US, where it continued declining. IR trends were increasing but were influenced by COVID-19, with differences in absolute values likely reflecting smooth vs. textured implant market share variations. Contextualizing epidemiology by surface type and geography remains fundamental.