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 most common cancer in American women with the average lifetime risk of 13%, or 1 in 8, next to skin cancer.²
• Breast cancer is the second leading cause of cancer death in women, accounting for approximately 7% of all cancer deaths.³ The odds that a woman will die from breast cancer is about 1 in 38 (about 2.6%).²
• Breast cancer death rates have remained steady in women younger than 50 since 2007, but have continued to decrease in older women, with noted death rate reductions of 1.3% per year from 2013-2017.²
• These decreases are believed to be the result of finding breast cancer earlier through screening and increased awareness, as well as better treatments.²

EPIDEMIOLOGY OF TRIPLE NEGATIVE BREAST CANCER (TNBC)

• Triple-negative breast cancers (TNBC) are a breast cancer subtype that lacks expression of both estrogen (ER) and progesterone (PR) hormone receptors, as well as human epidermal growth factor receptor 2 (HER2).¹
• TNBC comprises 10% of all female breast cancer cases by subtype, which also includes HR+/HER2- disease (68%), HR+/HER2+ disease (10%), HR-/HER2+ disease (4%) and unknown subtype (8%).¹
• As compared to the most common breast cancer subtype HR+/HER2- which is associated with 87 new cases per 100,000 women, the triple negative subtype accounts for just 13 new cases per 100,000¹
• 5-year relative survival rates can be impacted by subtype and staging:
  • Despite a total 5-year relative survival rate for all female breast cancers combined of 90%, the relative survival rate for TNBC is the worst at 76.7%¹
  • Stage at diagnosis may be the most powerful factor in determining survival outcome, as shown by relative survival rates for TNBC of 91.2% if disease is localized, but drops to 11.5% if disease is distant.¹

• Incidence and characteristics of TNBC can also vary by ethnicity:
  • 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
  • The highest rates of new TNBC cases have been demonstrated in black females.¹
  • Those diagnosed with subtypes of either TNBC or any HER2+ disease may be more likely to diagnosed at a younger age, belong to a minority group and be diagnosed at a later stage.¹

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 July 2020.
2. American Cancer Society, How Common Is Breast Cancer? Available: https://www.cancer.org/cancer/breast-cancer/about.html. Accessed July 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 July 2020.
4. O’Brien KM, Cole SR, Tse CK, et al.. Intrinsic breast tumor subtypes, race, and long-term survival in the Carolina Breast Cancer Study. Clin Cancer Res. 2010 Dec;16(24):6100-10.
5. American Cancer Society. Breast Cancer Facts and Figures 2019-2020. Available: https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/breast-cancer-facts-and-figures/breast-cancer-facts-and-figures-2019-2020.pdf. Accessed July 2020.