Epidemiology of Triple-Negative Breast Cancer: A Review

Abstract

Triple-negative breast cancer accounted for 12% of breast cancers diagnosed in the United States from 2012 to 2016, with a 5-year survival 8% to 16% lower than hormone receptor-positive disease. However, preventive and screening strategies remain tailored to the demographics of less lethal luminal cancers. This review examines the ethnic, genetic, and modifiable risk factors associated with triple-negative breast cancer, which providers must recognize to address the societal disparities of this deadly disease. Most notable is that triple-negative cancers disproportionately affect African American women and carriers of germline BRCA and PALB2 mutations. Even controlling for treatment delays, stage, and socioeconomic factors, African Americans with triple-negative breast cancer remain nearly twice as likely to die of their disease. To level the playing field, we must integrate genomic predictors of disease and epidemiologic characteristics of molecular breast cancer subtypes to provide personalized risk assessment, screening, and treatment for each patient.

FIGURE 1.

Rates of TNBC over time, by ethnicity. Solid lines indicate rates of TNBC. Dotted lines indicate rates of HR-negative cancer, scaled by race-specific proportion of HER2 negativity in HR-negative cancers, to provide a long-term estimate of TNBC with time.

FIGURE 2.

Relative rates of invasive female breast cancer subtypes by ethnicity, United States, 2012–2016.

FIGURE 3.

Germline mutations among patients with TNBC.