Breast cancer typically affects women age 50 and older, but it can also affect women and people AFAB who are younger than 50. Men and people assigned male at birth (AMAB) may also develop breast cancer. 

 

Breast cancer types

Healthcare providers determine cancer types and subtypes so they can tailor treatment to be as effective as possible with the fewest possible side effects. Common types of breast cancer include:

 

Invasive (infiltrating) ductal carcinoma (IDC): This cancer starts in your milk ducts and spreads to nearby breast tissue. It is the most common type of breast cancer in the United States.

Lobular breast cancer: This breast cancer starts in the milk-producing glands (lobules) in your breast and often spreads to nearby breast tissue. It is the second most common breast cancer in the United States.

Ductal carcinoma in situ (DCIS): Like IDC, this breast cancer starts in your milk ducts. The difference is DCIS does not spread beyond your milk ducts.

Less common breast cancer types include:

 

Triple-negative breast cancer (TNBC): This invasive cancer is aggressive and spreads more quickly than other breast cancers. 

Inflammatory breast cancer (IBC): This rare, fast-growing cancer looks like a rash on your breast. IBC is rare in the United States.

Pagets disease of the breast: This rare cancer affects the skin of your nipple and may look like a rash. Less than 4% of all breast cancers are Pagets disease of the breast.

Breast cancer subtypes

Healthcare providers classify breast cancer subtypes by receptor cell status. Receptors are protein molecules in or on cells surfaces. They can attract or attach to certain substances in your blood, including hormones like estrogen and progesterone. Estrogen and progesterone help cancerous cells to grow. Finding out if cancerous cells have estrogen or progesterone receptors helps healthcare providers plan breast cancer treatment.

 

Subtypes include:

 

ER-positive (ER+) breast cancers have estrogen receptors.

PR-positive (PR+) breast cancers have progesterone receptors.

HR-positive (HR+) breast cancers have estrogen and progesterone receptors.

HR-negative (HR-) breast cancers do not have estrogen or progesterone receptors.

HER2-positive (HER2+) breast cancers, which have higher than normal levels of the HER2 protein. This protein helps cancer cells to grow. About 15% to 20% of all breast cancers are HER2-positive.

 

Symptoms and Causes

 

Common signs of breast cancer and what to look for.

What are breast cancer symptoms?

The condition can affect your breasts in different ways. Some breast cancer symptoms are very distinctive. Others may simply seem like areas of your breast that look very different from any other area. Breast cancer may not cause noticeable symptoms either. But when it does, symptoms may include:

 

A change in the size, shape or contour of your breast.

A mass or lump, which may feel as small as a pea.

A lump or thickening in or near your breast or in your underarm that persists through your menstrual cycle.

A change in the look or feel of your skin on your breast or nipple. Your skin may look dimpled, puckered, scaly or inflamed. It may look red, purple or darker than other parts of your breast. 

A marble-like hardened area under your skin.

A blood-stained or clear fluid discharge from your nipple.

What causes breast cancer?

Experts know breast cancer happens when breast cells mutate and become cancerous cells that divide and multiply to create tumors. They are not sure what triggers that change. However, research shows there are several risk factors that may increase your chances of developing breast cancer. These include:

 

Age: Being 55 or older.

Sex: Women and people AFAB are much more likely to develop the condition than men and people AMAB.

Family history: If your parents, siblings, children or other close relatives have breast cancer, you are at risk of developing the disease.

Genetics: Up to 15% of people with breast cancer develop the disease because they have inherited genetic mutations. The most common genetic mutations involve the BRCA1 and BRCA2 genes. 

Smoking: Tobacco use has been linked to many different types of cancer, including breast cancer.

Drinking beverages containing alcohol: Research shows that drinking beverages containing alcohol may increase breast cancer risk.

Having obesity.

Radiation exposure: If you have had prior radiation therapy — especially to your head, neck or chest — you are more likely to develop breast cancer.

Hormone replacement therapy: People who use hormone replacement therapy (HRT) have a higher risk of being diagnosed with the condition.

What are the complications of breast cancer?

The most significant complication is metastatic breast cancer — breast cancer that spreads to other areas of your body, including your brain, bones, liver and lungs. Studies show about 1 in 3 women and people AFAB who have early-stage cancer later develop metastatic breast cancer.

 

Diagnosis and Tests

How is breast cancer diagnosed?

Healthcare providers may do physical examinations or order mammograms to check for signs of breast cancer. But they do the following tests to diagnose the disease:

 

Breast ultrasound.

Breast magnetic resonance imaging (MRI) scan.

Breast biopsy.

Immunohistochemistry test to check for hormone receptors. 

Genetic tests to identify mutations that cause breast cancer.

Stages of breast cancer

Healthcare providers use cancer staging systems to plan treatment. Staging cancer also helps providers set a prognosis, or what you can expect after treatment. Breast cancer staging depends on factors like breast cancer type, tumor size and location, and whether cancer has spread to other areas of your body. Breast cancer stages are:

 

Stage 0: The disease is noninvasive, meaning it has not spread from your breast ducts to other parts of your breast.

Stage I: There are cancerous cells in nearby breast tissue.

Stage II: The cancerous cells have formed a tumor or tumors. The tumor is either smaller than 2 centimeters across and has spread to underarm lymph nodes or larger than 5 centimeters across but has not spread to underarm lymph nodes. Tumors at this stage can measure anywhere between 2 and 5 centimeters across, and may or may not affect the nearby lymph nodes.

Stage III: There is breast cancer in nearby tissue and lymph nodes. Stage III is usually referred to as locally advanced breast cancer.

Stage IV: Cancer has spread from your breast to areas like your bones, liver, lungs or brain.

Management and Treatment

How is breast cancer treated?

Surgery is the primary breast cancer treatment, but healthcare providers may use other treatments. Breast cancer surgeries include:

 

Mastectomy.

Lumpectomy.

Breast reconstruction.

Providers may combine surgery with one or more of the following treatments:

 

Chemotherapy.

Radiation therapy, including intraoperative radiation therapy (IORT).

Immunotherapy.

Hormone therapy, including selective estrogen receptor modulator (SERM) therapy.

Targeted therapy.

What are treatment side effects?

Common chemotherapy and radiation therapy side effects include fatigue, nausea and vomiting. Targeted therapy, immunotherapy and hormone therapy have similar side effects, including gastrointestinal issues like constipation and diarrhea.

 

People react differently to breast cancer treatments. If you are receiving treatment, ask your healthcare provider how treatment may affect you, including how it may affect your daily life. Also, ask your provider about palliative care. Palliative care helps manage breast cancer symptoms and treatment side effects so you are as comfortable as possible as you go through treatment.

 

Complications of breast cancer surgery

All surgeries have potential complications, and breast cancer surgery is no exception. As you are considering your options, it is important to remember that surgery removes potentially life-threatening cancer. In general, the risks of breast cancer outweigh the complications.

 

If you are having breast cancer surgery, ask your healthcare provider to explain potential complications, which may include:

 

Infection at the surgical site.

Blood clots that can happen after surgery.

Nerve damage.

Lymphedema.

Prevention

Can breast cancer be prevented?

You may not be able to prevent breast cancer. But you can reduce your risk of developing it. Just as important, regular self-exams and mammograms can help detect breast cancer early on, when it is easier to treat.

 

How can I lower my risk?

There is no sure way to reduce breast cancer risk, but the American Cancer Society (ACS) has the following advice for all women and people AFAB:

 

Get to and stay at a healthy weight: This is a weight that is right for you. Ask a healthcare provider for information on setting up healthy weight management.

Eat a healthy diet: Some studies show a diet that includes vegetables, fruit, calcium-rich dairy foods and lean protein may reduce your risk of breast cancer. Avoiding red meat and processed meat may also reduce your risk.

Get moving: Studies show that regular physical activity lowers breast cancer risk.

Avoid beverages containing alcohol: Research shows a link between breast cancer and alcohol. The American Medical Association recommends women and people AFAB limit alcohol to one drink a day.

Get screened: Mammograms often detect tumors when they are too small to be felt.

Do regular self-exams: Examining your breasts regularly helps to maintain breast health and may allow you to find breast cancer tumors.

Some women and people AFAB have an increased risk for breast cancer because family members have it or they inherited a genetic mutation. If that is your situation, you may want to consider the following:

 

Genetic screening for breast cancer genes.

Medication that may lower breast cancer risk like tamoxifen, raloxifene or aromatase inhibitors.

Prophylactic (preventive) mastectomy.

Frequent breast cancer screenings and physical examinations. If you have an increased risk for breast cancer, ask your provider if you should have additional tests to detect breast cancer, particularly if you are under age 40 and have increased risk.