Breast cancer facts

• Breast cancer is the most common cancer among American women.
• One in every eight women in the United States develops breast cancer.
• There are many types of breast cancer that differ in their capability of spreading (metastasize) to other body tissues.
• The causes of breast cancer are not yet fully known, although a number of risk factors have been identified.
• There are many different types of breast cancer.
• Breast cancer symptoms and signs include
  • a lump in the breast or armpit,
  • bloody nipple discharge,
  • inverted nipple,
  • orange-peel texture or dimpling of the breast's skin,
  • breast pain or sore nipple,
  • swollen lymph nodes in the neck or armpit, and
  • a change in the size or shape of the breast or nipple.
• Breast cancer is diagnosed during a physical exam, by a self-exam of the breasts, mammography, ultrasound testing, and biopsy.
• Treatment of breast cancer depends on the type of cancer and its stage (0-IV) and may involve surgery, radiation, or chemotherapy.

According to the American Cancer society and the National Cancer Institute

• over 250,000 new cases of invasive breast cancer will be diagnosed each year in women and over 2,400 in men;
• approximately 40,610 women and 460 men die yearly;
• there are over 3.1 million breast cancer survivors in the United States;
• the five-year survival for all breast cancer patients is nearly 90%;
• although breast cancer awareness and survival has increased significantly in the United States for all races, several studies have cited a significantly worse survival rate for African-American women compared to white women; and
• guidelines for mammography differ depending on the organization making recommendations. Currently, the American Cancer Society recommends yearly mammograms for women aged 45-54 for women at average risk for breast cancer and mammograms every two years for women aged 55 and older, who should also have the option to continue yearly screening.

What is breast cancer?

Breast cancer definition

Breast cancer is a malignant tumor (a collection of cancer cells) arising from the cells of the breast. Although breast cancer predominantly occurs in women, it can also affect men. This article deals with breast cancer in women. Breast cancer and its complications can affect nearly every part of the body.

What are the statistics on male breast cancer?

Breast cancer is rare in men (approximately 2,400 new cases diagnosed per year in the U.S.) but typically has a significantly worse outcome. This is partially related to the often late diagnosis of male breast cancer, when the cancer has already spread.
Symptoms are similar to the symptoms in women, with the most common symptom being a lump or change in skin of the breast tissue or nipple discharge. Although it can occur at any age, male breast cancer usually occurs in men over 60 years of age.

What are the different types of breast cancer? Where does breast cancer come from?

There are many types of breast cancer. Some are more common than others, and there are also combinations of cancers. Some of the most common types of cancer are as follows:

• Ductal carcinoma in situ: The most common type of non-invasive breast cancer is ductal carcinoma in situ (DCIS). This early-stage breast cancer has not spread and therefore usually has a very high cure rate.
• Invasive ductal carcinoma: This cancer starts in the milk ducts of the breast and grows into other parts of the surrounding tissue. It is the most common form of breast cancer. About 80% of invasive breast cancers are invasive ductal carcinoma.
• Invasive lobular carcinoma: This breast cancer starts in the milk-producing glands of the breast. Approximately 10% of invasive breast cancers are invasive lobular carcinoma.
• The remainder of breast cancers are much less common and include the following:
• Mucinous carcinoma are formed from mucus-producing cancer cells. Mixed tumors contain a variety of cell types.
• Medullary carcinoma is an infiltrating breast cancer that presents with well-defined boundaries between the cancerous and noncancerous tissue.
• Inflammatory breast cancer: This cancer makes the skin of the breast appear red and feel warm (giving it the appearance of an infection). These changes are due to the blockage of lymph vessels by cancer cells.
• Triple-negative breast cancers: This is a subtype of invasive cancer with cells that lack estrogen and progesterone receptors and have no excess of a specific protein (HER2) on their surface. It tends to appear more often in younger women and African-American women.
• Paget's disease of the nipple: This cancer starts in the ducts of the breast and spreads to the nipple and the area surrounding the nipple. It usually presents with crusting and redness around the nipple.
• Adenoid cystic carcinoma: These cancers have both glandular and cystic features. They tend not to spread aggressively and have a good prognosis.
• Lobular carcinoma in situ: This is not a cancer but an area of abnormal cell growth. This pre-cancer can lead to invasive breast cancer later in life.

The following are other uncommon types of breast cancer:

• Papillary carcinoma
• Phyllodes tumor
• Angiosarcoma
• Tubular carcinoma

What causes breast cancer?

There are many risk factors that increase the chance of developing breast cancer. Although we know some of these risk factors, we don't know the cause of breast cancer or how these factors cause the development of a cancer cell.

We know that normal breast cells become cancerous because of mutations in the DNA, and although some of these are inherited, most DNA changes related to breast cells are acquired during one's life.
Proto-oncogenes help cells grow. If these cells mutate, they can increase growth of cells without any control. Such mutations are referred to as oncogenes. Such uncontrolled cell growth can lead to cancer.

What are breast cancer risk factors? How do you get breast cancer?

Some of the breast cancer risk factors can be modified (such as alcohol use) while others cannot be influenced (such as age). It is important to discuss these risks with a health care provider anytime new therapies are started (for example, postmenopausal hormone therapy).

Several risk factors are inconclusive (such as deodorants), while in other areas, the risk is being even more clearly defined (such as alcohol use).
The following are risk factors for breast cancer:

• Age: The chances of breast cancer increase as one gets older.
• Family history: The risk of breast cancer is higher among women who have relatives with the disease. Having a close relative with the disease (sister, mother, daughter) doubles a woman's risk.
• Personal history: Having been diagnosed with breast cancer in one breast increases the risk of cancer in the other breast or the chance of an additional cancer in the original breast.
• Women diagnosed with certain benign (non-cancerous) breast conditions have an increased risk of breast cancer. These include atypical hyperplasia, a condition in which there is abnormal proliferation of breast cells but no cancer has developed.
• Menstruation: Women who started their menstrual cycle at a younger age (before 12) or went through menopause later (after 55) have a slightly increased risk.
• Breast tissue: Women with dense breast tissue (as documented by mammogram) have a higher risk of breast cancer.
• Race: White women have a higher risk of developing breast cancer, but African-American women tend to have more aggressive tumors when they do develop breast cancer.
• Exposure to previous chest radiation or use of diethylstilbestrol increases the risk of breast cancer.
• Having no children or the first child after age 30 increases the risk of breast cancer.
• Breastfeeding for one and a half to two years might slightly lower the risk of breast cancer.
• Being overweight or obese increases the risk of breast cancer both in pre- and postmenopausal women but at different rates.
• Use of oral contraceptives in the last 10 years increases the risk of breast cancer slightly.
• Using combined hormone therapy after menopause increases the risk of breast cancer.
• Alcohol use increases the risk of breast cancer, and this seems to be proportional to the amount of alcohol used. A recent study reviewing the research on alcohol use and breast cancer concluded that all levels of alcohol use are associated with an increased risk for breast cancer. This includes even light drinking.
• Exercise seems to lower the risk of breast cancer.
• Genetic risk factors: The most common causes are mutations in the BRCA1 and BRCA2 genes (breast cancer and ovarian cancer genes). Inheriting a mutated gene from a parent means that one has a significantly higher risk of developing breast cancer.

What about antiperspirants or deodorants as causes of breast cancer?

Research has shown that parabens (a preservative used in deodorants) can build up in breast tissues. However, this study did not show that parabens cause breast cancer or that the parabens (which are found in many other products) were linked to the use of deodorants.

A 2002 study did not show any increased risk for breast cancer in women using an underarm deodorant or antiperspirant. A 2003 study showed an earlier age for breast cancer diagnosis in women who shaved their underarms more frequently and used underarm deodorants.

More research is needed to give us the answer about a relationship between breast cancer and underarm deodorants and blade shaving.

Are there any other questions I should ask my doctor about breast cancer?

Yes. There are surely other questions you will wish to ask. Do not hesitate to be very open about your concerns with your doctor. There is constantly new information and new research available about breast cancer, whether BRCA-related new treatments or drugs (for example, olaparib [Lynparza]) or new treatment regiments and recommendations. The foregoing questions and comments should demonstrate that the diagnosis and treatment of breast cancer may not be a simple process. Even when all the information is available, there may be difficulties in deciding a proper course of action. However, this decision-making process has a better chance of success when you and the doctor are well-informed and communicating effectively. Although the information here cannot be all-inclusive, we hope it will help you work through this process.

What tests do physicians use to diagnose breast cancer?

Although breast cancer can be diagnosed by the above signs and symptoms, the use of screening mammography has made it possible to detect many of the cancers early before they cause any symptoms.

The American Cancer Society (ACS) has the following recommendations for breast cancer screenings:

Women should have the choice to begin annual screening between 40-44 years of age. Women age 45 and older should have a screening mammogram every year until age 54. Women 55 years of age and older should have biennial screening or have the opportunity to continue screening annually. Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer.

Mammograms are a very good tool for breast cancer screening. As in any test, mammograms have limitations and will miss some cancers. An individual's family history and mammogram and breast exam results should be discussed with a health care provider.

The ACS does not recommend clinical screening exams in women of any age.
Women at high risk (greater than 20% lifetime risk) should get an MRI and a mammogram every year. Women at moderate risk (15%-20%) should talk to their doctor about the benefits and limitations of adding MRI screening to their yearly mammogram.

For about 20% of women with breast cancer, the cancer cells test positive for HER2. HER2 is a growth-promoting protein located on the surface of some cancer cells. HER2-positive breast cancers tend to grow more rapidly and spread more aggressively.

What tests detect HER2?

All patients with invasive breast cancer should have their tumor cells tested for HER2.

There are four tests for HER2. The interpretation of the tests should be discussed with your health care team. Health care professionals may use either immunohistochemistry (IHC) to identify the HER2 protein or in-situ hybridization (ISH) testing to look for the gene.

IHC test: This tests shows if there is too much HER2 protein in the cancer cells and is graded 0 to 3.

FISH test: This test evaluates if there are too many copies of the HER2 gene in the cancer cells. This test is either positive or negative.

SPoT-Light HER2 CISH test: This test also evaluates if there are too many copies of the HER2 gene in the cancer cells and is reported as positive or negative.

Inform HER2 Dual ISH test: This test also evaluates if there are too many copies of the HER2 gene in the cancer cells and is reported as positive or negative.

Do symptoms and signs of HER2-positive breast cancer differ from those of HER2-negative breast cancer?

The signs and symptoms for HER2-positive breast cancers are the same as for HER2-negative breast cancers, except for the fact that HER2-positive cancers grow faster and are more likely to spread.

What are therapies for HER2-positive breast cancers?

All therapy needs to be evaluated by your health care team and guided in response to all test results available and the specific circumstances of your cancer.

There are targeted therapies for HER2-positive breast cancers; a number of drugs are available to target this protein:

• Trastuzumab (Herceptin): a monoclonal antibody given by itself or with chemotherapy to treat HER2-positive breast cancers
• Pertuzumab (Perjeta): another monoclonal antibody that targets HER2-positive cancers
• Ado-trastuzumab emtansine or TDM-1 (Kadcyla): a monoclonal antibody that is attached to a chemotherapy drug
• Lapatinib (Tykerb): a kinase inhibitor usually used in adjunct with chemotherapy or hormone therapy

How do health care professionals determine breast cancer staging?

Staging is the process of determining the extent of the cancer and its spread in the body. Together with the type of cancer, staging is used to determine the appropriate therapy and to predict chances for survival.

To determine if the cancer has spread, several different imaging techniques can be used.

• Chest X-ray: It looks for spread of the cancer to the lung.
• Mammograms: More detailed and additional mammograms provide more images of the breast and may locate other abnormalities.
• Computerized tomography (CT scan): These specialized X-rays are used to look at different parts of your body to determine if the breast cancer has spread. It could include a CT of the brain, lungs, or any other area of concern.
• Bone scan: A bone scan determines if the cancer has spread (metastasized) to the bones. Low level radioactive material is injected into the bloodstream, and over a few hours, images are taken to determine if there is uptake in certain bone areas, indicating metastasis.
• Positron emission tomography (PET scan): A radioactive material is injected that is absorbed preferentially by rapidly growing cells (such as cancer cells). The PET scanner then locates these areas in your body.

Staging system

This system is used by a health care team to summarize in a standard way the extent and spread of the cancer. This staging can then be used to determine the treatment most appropriate for the type of cancer.

The most widely used system in the U.S. is the American Joint Committee on Cancer TNM system. A new eighth edition of this staging system has been developed for 2018 that includes results of testing for certain biomarkers, including the HER2 protein and the results of gene expression assays, in addition to the factors (TNM) described below.

Besides the information gained from the imaging tests, this system also uses the results from surgical procedures. After surgery, a pathologist looks at the cells from the breast cancer as well as from the lymph nodes. This information gained is incorporated into the staging as it tends to be more accurate than the physical exam and X-ray findings alone.

TNM staging. This system uses letters and numbers to describe certain tumor characteristics in a uniform manner. This allows health care providers to stage the cancer (which helps determine the most appropriate therapy) and aids communication among health care providers.

T: This describes the size of the tumor. It is followed by a number from 0 to 4. Higher numbers indicate a larger tumor or greater spread:

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• T1: Tumor is 2 cm or less across
• T2: Tumor is 2 cm-5 cm
• T3: Tumor is more than 5 cm
• T4: Tumor of any size growing into the chest wall or skin

N: This describes the spread to lymph node near the breast. It is followed by a number from 0 to 3.

• NX: Nearby lymph nodes cannot be assessed (for example if they have previously been removed).
• N0: There has been no spread to nearby lymph nodes. In addition to the numbers, this part of the staging is modified by the designation "i+" if the cancer cells are only seen by immunohistochemistry (a special stain) and "mol+" if the cancer could only be found using PCR (special detection technique to detect cancer at the molecular level).
• N1: Cancer has spread to one to three axillary lymph nodes (underarm lymph nodes) or tiny amounts of cancer are found in internal mammary lymph nodes (lymph nodes near breastbone).
• N2: Cancer has spread to four to nine axillary lymph nodes or the cancer has enlarged the internal mammary lymph nodes.
• N3: Any of the conditions below
  • Cancer has spread to 10 or more axillary lymph nodes with at least one cancer spread larger than 2 mm.
  • Cancer has spread to lymph nodes under the clavicle with at least area of cancer spread greater than 2 mm.

M: This letter is followed by a 0 or 1, indicating whether the cancer has spread to other organs.

• MX: Metastasis cannot be assessed.
• M0: No distant spread is found on imaging procedures or by physical exam.
• M1: Spread to other organs is present.

Once the T, N, and M categories have been determined, they are combined into staging groups. There are five major staging groups, stage 0 to stage IV, which are subdivided into A and B, or A and B and C, depending on the underlying cancer and the T, N, and M scale.

Cancers with similar stages often require similar treatment.