Oncology Nurses

HER2-negative Breast Cancer Epidemiology

BREAST CANCER

  • According to the American Cancer Society and National Cancer Institute, the current estimates for breast cancer for the year 2020 include:2
    • Incidence of female breast cancer estimated to be 276,480 new cases.2,3
    • About 48,530 new cases of carcinoma in situ (CIS) will be diagnosed (CIS is non-invasive and is the earliest form of breast cancer).2
    • About 42,170 women will die from breast cancer.2,3
  • Breast cancer is the second leading cause of cancer death in women (only lung cancer kills more women each year), accounting for approximately 7% of all cancer deaths.3 The chance that a woman will die from breast cancer is about 1 in 38 (about 2.6%).2
  • Since 2007, breast cancer death rates have been steady in women younger than 50 but have continued to decrease in older women. From 2013 to 2017, the death rate decreased by 1.3% per year.2
  • These decreases are believed to be the result of finding breast cancer earlier through screening and increased awareness, as well as better treatments.2

HER2-negative (HER2-) BREAST CANCER

  • Breast cancer is classified into four main subtypes, utilizing hormone receptor and HER2 receptor status for differentiation.1
    • HER2- breast cancers comprise two of these subtypes, distinguished by hormone receptor status – hormone receptor positive (HR+), also known as “Luminal A” and hormone receptor negative (HR-), also known as “Triple Negative”.1
    • These two breast cancer subtypes account for 100 new breast cancer cases per 100,000 women, with the majority being HR+ (HR+ = 87 and HR- = 13).1
    • The HR+/HER2- subtype is the most common of all the breast cancer subtypes, occurring at a rate 6 times higher than triple-negative and HR+/HER2-positive (HER2+) breast cancers, as well as 15 times higher than HR-/HER2+ breast cancer.1
    • In comparing the different subtypes, HER2- constitutes 78% of all female breast cancer cases.1

  • Survival rates for HER2- breast cancers can vary by subtype:
    • Although this subtype is the most common, the 5-year relative survival of patients with HR+/HER2- breast cancer is 94.1%, the best of all breast cancer subtypes.1
    • In contrast, the 5-year relative survival of patients with HR-/HER2– breast cancers is the least-favorable of all breast cancer subtypes at 76.7%.1

  • Staging of disease can significantly impact 5-year relative survival rates:
    • Relative survival with subtype HR+/HER2- breast cancer is 100% if disease is localized, 89.9% if disease is regional and only 4% if disease is distant.1
    • Similarly, relative survival with subtype HR-/HER2- breast cancer is 91.2% if disease is localized, 65.0% if disease is regional and 11.5% if disease is distant.1
  • Incidence of HER2- breast cancers can also vary by ethnicity:
    • HR+/HER2- ethnic/race distribution of (out of every 100,000 women diagnosed with breast cancer): 91.3 (White), 71.3 (Black), 51.7 (American Indian/Alaska Native), 68.7 (Asian/Pacific Islander) and 63.4 (Hispanic).1
    • In the Carolina Breast Cancer Study (compared with white women (n=631), African American women (n = 518) were less likely to have HR+/HER2- disease (48 versus 64 percent, respectively) and more likely to have triple negative disease (22 versus 11 percent, respectively).4

Sources and Additional Reading

  1. National Cancer Institute, Surveillance, Epidemiology, and End Results Program. Cancer Stat Facts: Female Breast Cancer Subtypes. Available: https://seer.cancer.gov/statfacts/html/breast-subtypes.html. Accessed June 2020.
  2. American Cancer Society, How Common Is Breast Cancer? Available: https://www.cancer.org/cancer/breast-cancer/about.html. Accessed June 2020.
  3. National Cancer Institute, Surveillance, Epidemiology, and End Results Program. Cancer Stat Facts: Cancer Stat Facts: Female Breast Cancer. Available: https://seer.cancer.gov/statfacts/html/breast.html. Accessed June 2020.
  4. Intrinsic breast tumor subtypes, race, and long-term survival in the Carolina Breast Cancer Study. AU O’Brien KM, Cole SR, Tse CK, Perou CM, Carey LA, Foulkes WD, Dressler LG, Geradts J, Millikan RC SO. Clin Cancer Res. 2010 Dec;16(24):6100-10.