Breast Cancer

Overview

Breast cancer is cancer that forms in the cells of the breasts.

After skin cancer, breast cancer is the most common cancer diagnosed in women in the United States. Breast cancer can occur in both men and women, but it's far more common in women.

Substantial support for breast cancer awareness and research funding has helped created advances in the diagnosis and treatment of breast cancer. Breast cancer survival rates have increased, and the number of deaths associated with this disease is steadily declining, largely due to factors such as earlier detection, a new personalized approach to treatment and a better understanding of the disease.

Breast cancers can start from different parts of the breast. The breast is an organ that sits on top of the upper ribs and chest muscles. There is a left and right breast and each one has mainly glands, ducts, and fatty tissue. In women, the breast makes and delivers milk to feed newborns and infants. The amount of fatty tissue in the breast determines the size of each breast.

The breast has different parts:

Lobules are the glands that make breast milk. Cancers that start here are called lobular cancers.

Ducts are small canals that come out from the lobules and carry the milk to the nipple. This is the most common place for breast cancer to start. Cancers that start here are called ductal cancers.

The nipple is the opening in the skin of the breast where the ducts come together and turn into larger ducts so the milk can leave the breast. The nipple is surrounded by slightly darker thicker skin called the areola. A less common type of breast cancer called Paget disease of the breast can start in the nipple.

The fat and connective tissue (stroma) surround the ducts and lobules and help keep them in place. A less common type of breast cancer called phyllodes tumor can start in the stroma.

Blood vessels and lymph vessels are also found in each breast. Angiosarcoma is a less common type of breast cancer that can start in the lining of these vessels. The lymph system is described below.

A small number of cancers start in other tissues in the breast. These cancers are called sarcomas and lymphomas and are not really thought of as breast cancers.

breast cancer spreads

Breast cancer can spread when the cancer cells get into the blood or lymph system and then are carried to other parts of the body. 

The lymph (or lymphatic) system is a part of your body's immune system. It is a network of lymph nodes (small, bean-sized glands), ducts or vessels, and organs that work together to collect and carry clear lymph fluid through the body tissues to the blood. The clear lymph fluid inside the lymph vessels contains tissue by-products and waste material, as well as immune system cells.

The lymph vessels carry lymph fluid away from the breast. In the case of breast cancer, cancer cells can enter those lymph vessels and start to grow in lymph nodes. Most of the lymph vessels of the breast drain into:

Lymph nodes under the arm (axillary lymph nodes)

Lymph nodes inside the chest near the breastbone (internal mammary lymph nodes)

Lymph nodes around the collar bone (supraclavicular [above the collar bone] and infraclavicular [below the collar bone] lymph nodes)

If cancer cells have spread to your lymph nodes, there is a higher chance that the cells could have traveled through the lymph system and spread (metastasized) to other parts of your body. Still, not all women with cancer cells in their lymph nodes develop metastases, and some women with no cancer cells in their lymph nodes might develop metastases later.

Symptoms

Different people have different symptoms of breast cancer. Some people do not have any signs or symptoms at all.

• Some warning signs of breast cancer are—
• New lump in the breast or underarm (armpit).
• Thickening or swelling of part of the breast.
• Irritation or dimpling of breast skin.
• Redness or flaky skin in the nipple area or the breast.
• Pulling in of the nipple or pain in the nipple area.
• Nipple discharge other than breast milk, including blood.
• Any change in the size or the shape of the breast.
• Pain in any area of the breast.

Keep in mind that these symptoms can happen with other conditions that are not cancer.

If you have any signs or symptoms that worry you, be sure to see your doctor right away.

Causes

After puberty, a female’s breasts are made up of fat, connective tissue, and thousands of lobules. These are tiny glands that can produce milk. Tiny tubes, or ducts, carry the milk toward the nipple.

Breast cancer develops as a result of genetic mutations or damage to DNA. These can be associated withTrusted Source exposure to estrogen, inherited genetic defects, or inherited genes that can cause cancer, such as the BRCA1 and BRCA2 genes.

When a person is healthy, their immune system attacks any abnormal DNA or growths. When a person has cancer, this does not happen.

As a result, cells within breast tissue begin to multiply uncontrollably, and they do not die as usual. This excessive cell growth forms a tumor that deprives surrounding cells of nutrients and energy.

Breast cancer usually starts in the inner lining of the milk ducts or the lobules that supply them with milk. From there, it can spread to other parts of the body.

DIAGNOSIS AND TESTS

Your healthcare provider will perform a breast examination and ask about your family history, medical history and any existing symptoms. Your healthcare provider will also recommend tests to check for breast abnormalities. These tests may include:

Mammogram. These special X-ray images can detect changes or abnormal growths in your breast. A mammogram is commonly used in breast cancer prevention.

Ultrasonography. This test uses sound waves to take pictures of the tissues inside of your breast. It’s used to help diagnose breast lumps or abnormalities.

Positron emission tomography (PET) scanning: A PET scan uses special dyes to highlight suspicious areas. During this test, your healthcare provider injects a special dye into your veins and takes images with the scanner.

Magnetic resonance imaging (MRI): This test uses magnets and radio waves to produce clear, detailed images of the structures inside of your breast.

If your healthcare provider sees anything suspicious on the imaging tests, they may take a biopsy of your breast tissue. They’ll send the sample to a pathology lab for analysis.

breast cancer stages

Staging helps describe how much cancer is in your body. It’s determined by several factors, including the size and location of the tumor and whether the cancer has spread to other areas of your body. The basic breast cancer stages are:

Stage 0. The disease is non-invasive. This means it hasn’t broken out of your breast ducts.

Stage I. The cancer cells have spread to the nearby breast tissue.

Stage II. The tumor is either smaller than 2 centimeters across and has spread to underarm lymph nodes or larger than 5 centimeters across but hasn’t spread to underarm lymph nodes. Tumors at this stage can measure anywhere between 2 to 5 centimeters across, and may or may not affect the nearby lymph nodes.

Stage III. At this stage, the cancer has spread beyond the point of origin. It may have invaded nearby tissue and lymph nodes, but it hasn’t spread to distant organs. Stage III is usually referred to as locally advanced breast cancer.

Stage IV. The cancer has spread to areas away from your breast, such as your bones, liver, lungs or brain. Stage IV breast cancer is also called metastatic breast cancer.

MANAGEMENT AND TREATMENT

There are several breast cancer treatment options, including surgery, chemotherapy, radiation therapy, hormone therapy, immunotherapy and targeted drug therapy. What’s right for you depends on many factors, including the location and size of the tumor, the results of your lab tests and whether the cancer has spread to other parts of your body. Your healthcare provider will tailor your treatment plan according to your unique needs. It’s not uncommon to receive a combination of different treatments, too.

Breast cancer surgery

Breast cancer surgery involves removing the cancerous portion of your breast and an area of normal tissue surrounding the tumor. There are different types of surgery depending on your situation, including:

Lumpectomy. Also called a partial mastectomy, a lumpectomy removes the tumor and a small margin of healthy tissue around it. Typically, some of the lymph nodes — in your breast or under your arm — are also removed for evaluation. People who have a lumpectomy often have radiation therapy in the weeks following the procedure.

Mastectomy. Removal of your entire breast is another option. In some cases, doctors can perform a nipple-sparing mastectomy to preserve your nipple and areola (the dark skin around your nipple). Many women choose to undergo either immediate or delayed breast reconstruction following their mastectomy.

Sentinel node biopsy. Because early detection of breast cancer has resulted in the lymph nodes being negative (for cancer) in most cases, the sentinel node biopsy was developed to prevent the unnecessary removal of large numbers of lymph nodes that aren’t involved by the cancer. To identify the sentinel lymph node, doctors inject a dye that tracks to the first lymph node that cancer would spread to. If that lymph node is cancer-free, then other lymph nodes don’t need to be removed. If that lymph node has cancer in it, it may be necessary to remove additional lymph nodes. Often, there’s more than one sentinel node identified, but the fewer lymph nodes removed the lower the chance of developing swelling in your arm (lymphedema). A sentinel lymph node biopsy can be done with either a lumpectomy or a mastectomy.

Axillary lymph node dissection. If multiple lymph nodes are involved by the cancer, an axillary lymph node dissection may be done to remove them. This means removing many of the lymph nodes under your arm (your axilla).

Modified radical mastectomy. During this procedure, your entire breast is removed in addition to your nipple. Nearby lymph nodes in your underarm area are also removed, but your chest muscles are left intact. Breast reconstruction can often be an option if desired.

Radical mastectomy. This procedure is rarely performed today unless the breast cancer has spread to your chest wall muscles. During a radical mastectomy, your surgeon removes your entire breast, your nipple, underarm lymph nodes and chest wall muscles. People who undergo this procedure may choose to have breast reconstruction as well.

Chemotherapy for breast cancer

Your healthcare provider may recommend chemotherapy for breast cancer before a lumpectomy in an effort to shrink the tumor. Sometimes, it’s given after surgery to kill any remaining cancer cells and reduce the risk of recurrence (coming back). If the cancer has spread beyond your breast to other parts of your body, then your healthcare provider may recommend chemotherapy as a primary treatment.

Radiation therapy for breast cancer

Radiation therapy for breast cancer is typically given after a lumpectomy or mastectomy to kill remaining cancer cells. It can also be used to treat individual metastatic tumors that are causing pain or other problems.

Hormone therapy for breast cancer

Some types of breast cancer use hormones — such as estrogen and progesterone — to grow. In these cases, hormone therapy can either lower estrogen levels or stop estrogen from attaching to breast cancer cells. Most often, healthcare providers use hormone therapy after surgery to reduce the risk of breast cancer recurrence. However, they may also use it before surgery to shrink the tumor or to treat cancer that has spread to other parts of your body.

Immunotherapy for breast cancer

Immunotherapy uses the power of your own immune system to target and attack breast cancer cells. Treatment is given intravenously (through a vein in your arm or hand). Your healthcare provider might use immunotherapy for breast cancer in combination with chemotherapy.

Targeted drug therapy for breast cancer

Some drugs can target specific cell characteristics that cause cancer. Your healthcare provider might recommend targeted drug therapy in cases where breast cancer has spread to other areas of your body. Some of the most common drugs used in breast cancer treatment include monoclonal antibodies (like trastuzumab, pertuzumab and margetuximab), antibody-drug conjugates (like ado-trastuzumab emtansine and fam-trastuzumab deruxtecan) and kinase inhibitors (such as lapatinib, neratinib and tucatinib).

PREVENTION

While you can’t prevent breast cancer altogether, there are certain things you can do to reduce your risk of discovering it at an advanced stage. For example:

Get routine mammograms. The American Cancer Society recommends having a baseline mammogram at age 35, and a screening mammogram every year after age 40.

Examine your breasts every month after age 20. You’ll become familiar with the contours and feel of your breasts and will be more alert to changes.

Have your breasts examined by a healthcare provider at least once every three years after age 20, and every year after age 40. Clinical breast exams can detect lumps that mammograms may not find.

OUTLOOK / PROGNOSIS

If you’ve been diagnosed with breast cancer, your healthcare provider will talk with you in detail about your treatment options. Treatment and recovery will be different for everyone, so they can tell you what to expect in your situation.

People with early-stage breast cancer often manage their condition successfully with treatment. In fact, many people who’ve received a breast cancer diagnosis go on to live long, fulfilling lives. Late-stage breast cancer is more difficult to treat, however, and can be fatal.

he overall five-year survival rate for breast cancer is 90%. This means that 90% of people diagnosed with the disease are still alive five years later. The five-year survival rate for breast cancer that has spread to nearby areas is 86%, while the five-year survival rate for metastatic breast cancer is 28%. Fortunately, the survival rates for breast cancer are improving as we learn more about the disease and develop new and better approaches to management.

Keep in mind that survival rates are only estimates. They can’t predict the success of treatment or tell you how long you’ll live. If you have specific questions about breast cancer survival rates, talk to your healthcare provider.

LIVING WITH

In addition to having routine checkups and mammograms, you should call your healthcare provider if you notice any changes in your breasts.

Learning everything you can about your diagnosis can help you make informed decisions about your health. Here are some questions you may want to ask your healthcare provider:

• Where is the tumor located?
• Has the tumor spread?
• What stage breast cancer do I have?
• What do the estrogen receptor (ER), progesterone receptor (PR) and HER2 tests show and what do the results mean for me?
• What are my treatment options?
• Is breast cancer surgery an option for me?
• Will I be able to work while I undergo treatment?
• How long will my treatment last?
• What other resources are available to me?
• A note from Cleveland Clinic

Being diagnosed with breast cancer can feel scary, frustrating and even hopeless. If you or a loved one is facing this disease, it’s important to take advantage of the many resources available to you. Talk to your healthcare provider about your treatment options. You may even want to get a second opinion before making a decision. You should feel satisfied and optimistic about your treatment plan. Finally, joining a local support group can help with feelings of isolation and allow you to talk with other people who are going through the same thing.