Breast Cancer Overview: What You Need to Know

Understanding Breast Cancer

Breast cancer has likely touched the lives of people you know. According to the National Breast Cancer Foundation, roughly 1 in 8 U.S. women will develop breast cancer over the course of her lifetime.1

Breast cancer is the most common cancer among American women, with the exception of skin cancers. Furthermore, it is estimated that in 2022, approximately 30% of all new women cancer diagnoses will be breast cancer.2

Early detection is key in the fight against breast cancer. Let’s review breast cancer facts and explore the promising future of breast cancer screening, diagnosis, and care.

What is breast cancer?

Breast cancer is a disease in which cancer cells form in the tissues of the breast. Overtime, cancer cells can invade surrounding tissues within the breast including within the lobules, ducts, nipple, or in the fat and connective tissue known as the stroma.  

Additionally, breast cancer can metastasize (spread) via the blood or lymph to other parts of the body. 

Types of breast cancer

There are many different types of breast cancer which are defined based on where they originate, how much they have grown or spread, and features that influence how the cancer might act.

Most breast cancers are invasive, meaning the cancer has spread from the original site to other areas of the body.

The most common type of breast cancer, accounting for approximately 80% of all cases, is called invasive ductal carcinoma (IDC).3 IDC is a cancer that begins in a milk duct (the tubes in the breast that carry milk to the nipple) and grows into other parts of the breast.

The second most common breast cancer, accounting for roughly 5% to 10% of all breast cancers, is called invasive lobular carcinoma (ILC) ILC begins in lobules, where breast milk is made, and then can spread to breast tissue nearby.3 

Non-invasive breast cancer, also known as in situ breast cancer, remains in a specific location of the breast, without spreading to surrounding tissue, lobules, or ducts. 

The two most common types of in situ cancers are ductal carcinoma and lobular carcinoma.3


Breast cancer risk factors

While there are known risk factors for breast cancer, most cases can’t be linked to a specific cause. However, the following are some known risk factors for developing breast cancer:


The chance of getting breast cancer increases with age. Approximately 80% of breast cancers are discovered in women over the age of 50.2

Reproductive and menstrual history

Research suggests that there is a link between menstrual and pregnancy history and the risk of breast cancer. For example, women who experience the onset of menstruation before the age of 12, may be at higher risk for developing breast cancer. Additionally, women who experience late onset of menopause (after the age of 55) may also be at a higher risk of breast cancer.4 

Individual history of breast cancer

A person who has had a history of breast cancer, is at higher risk for developing the development of subsequent breast cancer over time.5

Genetic factors

Roughly 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they are the direct result of gene mutations passed on from a parent. The most common cause of hereditary breast cancer is a mutation in the BRCA1 or BRCA2 gene.3

Alcohol intake

According to the American Cancer Society, even drinking small amounts of alcohol is linked with an increased risk of breast cancer in women. Research has shown that light drinkers have a slightly increased risk of developing breast cancer, compared with nondrinkers. Breast cancer risk increase is increased in moderate drinkers and even more so for heavy drinkers. 

The increased risk may be attributed to the fact that alcohol can raise estrogen levels in the body.6


Hormonal changes

Many breast cancers are hormone receptor-positive, meaning they require hormones like estrogen in order to grow. Emerging research suggests that your gut microbiome may influence estrogen metabolism and in turn, estrogen levels. 

One 2021 study found that gut dysbiosis (an imbalance of healthy gut bacteria) may play a role in the development of certain breast cancers.7

Researchers theorize that being able to correct gut dysbiosis through diet and nutrition may be helpful.7


The connection between obesity and breast cancer

Studies continually show that there is a link between obesity and the development of many cancers, including breast cancer.8

For breast cancer, the connection is strongest for postmenopausal women and for the development of estrogen receptor positive (ER+) breast cancer. After menopause, adipose (fat) tissue is the main source of estrogen production in the body. Therefore, estrogen appears to be a driving force in obesity-related development of breast cancer.8

There is research to suggest that gut dysbiosis can lead to obesity. Considering obesity is a known risk factor for breast cancer, restoring optimal balance in the gut may be a focused approach against obesity and its associated breast cancer risk.7

Early detection of breast cancer

Regular breast cancer screenings can help detect the disease in its earliest stages which can prevent further spreading. 

The American Cancer Society recommends that women begin screening with a mammogram starting at 40 years old. Women with a strong family history, or those with a genetic predisposition to the disease should get a yearly breast MRI in addition to a mammogram starting around the age of 30.3

Continuing research is looking at ways to improve current breast cancer screening options. For example, technological advances in imaging can improve screening tools and further promote early detection. 

The future of breast cancer care

Promising research continues to find better ways to detect and treat breast cancer. 

For example, a newer type of mammogram has been developed called digital breast tomosynthesis, also known as three-dimensional (3D). The procedure takes images from different angles around the breast and can help detect cancer even in its earliest stages.3

Additionally, positron emission mammography (PEM) is a newer imaging test of the breast that combines some features of a PET (positron emission tomography) scan and a mammogram. It may be more effective in detecting small clusters of cancer cells within the breast than a mammogram.9 

Immunotherapy for cancer treatment works by stimulating a person’s immune system to target and fight the disease. Emerging research in the field of nano-immunotherapy is focusing on the development of new nanoparticles for breast cancer treatment.9 

Nanoparticles are pharmaceutical carriers that can deliver treatments with more precision and can infiltrate tumors more deeply. Additionally, nanoparticles can reduce the damage that treatment can cause to the surrounding healthy organs and tissues.

Furthermore, just this year the FDA approved the first targeted therapy (T-DXd) for patients with HER2-low breast cancer that has spread to other parts of the body.9

Scientists around the world are working to further revolutionize our understanding of how to prevent and treat breast cancer more effectively to improve outcomes for breast cancer patients.



  1. Breast Cancer Facts & Statistics for 2022. (2022). Accessed October12, 2022 from

  2. Giaquinto, A.N., Sung, H., Miller, K.D., Kramer, J.L., Newman, L.A., Minihan, A., Jemal, A. and Siegel, R.L. (2022), CA A Cancer J Clin.

  3. American Cancer Society. Cancer Statistics Center. Accessed October 10, 2022. 

  4.  Olsson HL, Olsson ML. Front Oncol. 2020 Jan 24;10:21. doi: 10.3389/fonc.2020.00021. PMID: 32038990; PMCID: PMC6993118.

  5.  David V. Schacht, Ken Yamaguchi, Jessica Lai, Kirti Kulkarni, Charlene A. Sennett, and Hiroyuki Abe. American Journal of Roentgenology 2014 202:2, 289-292

  6.  LoConte NK, Brewster AM, Kaur JS, Merrill JK, Alberg AJ. Journal of Clinical Oncology 2018; 36(1):83–93.

  7.  Ruo SW, Alkayyali T, Win M, Tara A, Joseph C, Kannan A, Srivastava K, Ochuba O, Sandhu JK, Went TR, Sultan W, Kantamaneni K, Poudel S. Cureus. 2021 Aug 26;13(8):e17472. doi: 10.7759/cureus.17472. PMID: 34513524; PMCID: PMC8405251.Keshavarz K, Jafari M, Lotfi F, Bastani P, Salesi M, Gheisari F, Rezaei Hemami M. Med J Islam Repub Iran. 2020 Aug 18;34:100. doi: 10.34171/mjiri.34.100. PMID: 33315994; PMCID: PMC7722955.

  8.  Bhardwaj P, Au CC, Benito-Martin A, Ladumor H, Oshchepkova S, Moges R, Brown KA. J Steroid Biochem Mol Biol. 2019 May;189:161-170. doi: 10.1016/j.jsbmb.2019.03.002. Epub 2019 Mar 6. PMID: 30851382; PMCID: PMC6502693.Li Y, Miao W, He D, Wang S, Lou J, Jiang Y, Wang S. Front Bioeng Biotechnol. 2021 Jun 2;9:680315. doi: 10.3389/fbioe.2021.680315. PMID: 34150736; PMCID: PMC8207056.

  9.  Bartsch, R., Berghoff, A.S., Furtner, J. et al. Nat Med 28, 1840–1847 (2022).