Breast Cancer

Breast cancer at a glance

  • Breast cancer is the out-of-control growth of cells in the breast that results in a malignant, cancerous tumor.
  • According to the National Institutes of Health, one in eight women will get breast cancer and it is the second most prevalent type of cancer death among women.
  • A mammogram is the best way to detect breast caner in its earlier, more treatable stage.
  • The most common breast cancer symptom is a new mass or lump in the breast.
  • Breast cancer causes are not completely known, but risk factors for breast cancer include age, personal health, genetics and lifestyle issues such as obesity.
  • Treatment for breast cancer can involve surgery, radiation, chemotherapy and hormone therapy.

Breast cancer causes

Breast cancer is when normal cells in the breast begin to grow out of control and result in a cancerous tumor. These cancerous cells can spread, or metastasize, to other parts of the body.

Men can get breast cancer, but they are about 100 times less likely to than women, according to the American Cancer Society (ACS).

Breast cancer usually begins in the cells that line the ducts that carry milk from the lobules, where milk is produced, to the nipples. These are called ductal cancers (invasive ductal carcinoma) and account for about 80 percent of breast cancer cases. Lobular cancers (invasive lobular carcinoma) begin in the cells lining the lobule.

Breast cancer can also form in the breast stroma, comprised of fatty tissue, connective tissue, blood vessels and lymphatic vessels.

According to the ASC, breast cancer is the second most common cancer among women in the U.S. after skin cancer. Breast cancer accounts for one in three cancers women experience.

It is not completely known what causes breast cancer. As with other cancers, the cause of breast cancer is most likely a combination of genetic, environmental and lifestyle factors.

It is important to identify breast cancer as early as possible, because treatment will be easier for the patient, more likely to be successful and can potentially prevent the cancer from metastasizing. Examination and diagnosis options are described below.

Breast cancer risk factors

The ACS reports that most women with more than two risk factors for breast cancer never get the disease, and many women with no risk factors do. Also, risk factors can change over time in an individual.

Risk factors that one cannot change

Risk of breast cancer increases with age. Women under age 45 account for about 1 in 8 cases of invasive breast cancer, while women age 55 or older experience 2 out of 3 cases.

Gene mutations inherited from a parent cause up to 10 percent of breast cancer cases, according to the ACS. The BRCA1 and BRCA2 genetic mutations are the most common hereditary risk factor. Lifetime breast cancer risk, says the ACS, from BRCA1 is 55-65 percent on average, and about 45 percent for BRCA2. Other genetic factors involve less risk for breast cancer and include effects from mutations of such genes as ATM, TP53, PTEN, CHEK2 and others.

Family and personal histories. A woman whose mother or sister has had breast cancer has about double the risk over women without such a family history. If a woman has had breast cancer in one breast, her risk of breast cancer in the other breast or in that one again is increased.

African-American women are overall less likely to get breast cancer than white women but they are more likely to die of it than white women when they do get it. Native Americans, Asian and Hispanic women have a lower risk of getting breast cancer, and from dying of it, than other races.

Physical factors. Higher breast density (more glandular and fibrous tissue than fatty tissue) increases the risk of breast cancer. The presence of certain benign breast lesions can also increase risk of breast cancer. Other physical factors include:

  • Previous chest radiation
  • Exposure to DES (diethylstilbestrol), given to some pregnant women between the1940s and the early 70s
  • Beginning menstruation before age 12
  • Entering menopause after age 55
  • Atypical hyperplasia or other breast diseases
  • Not bearing a child or having one at a later age.

Lifestyle risk factors that can be changed

Some personal health and lifestyle choices can increase a woman’s risk for breast cancer. Even though there is no way of knowing if having one of these risk factors means a woman will get breast cancer, physicians advise that women make lifestyle changes to eliminate or reduce these risk factors:

  • Drinking alcohol increases one’s risk, limit consumption to one drink a day (less for women with family history of breast cancer)
  • Being obese or overweight
  • High saturated-fat diet
  • Not enough exercise
  • Taking oral birth control
  • Hormone therapy of estrogen/progestin after menopause for several years
  • Not breastfeeding (the more months breastfeeding the lower the risk)
  • Gaining weight and extra fat after menopause, which may raise estrogen levels.

Breast cancer symptoms

Symptoms of breast cancer generally involve a change in a woman’s breast, most often a new lump or a mass. Breast cancers that do cause symptoms are more likely to have already spread to other parts of the body and are more difficult to treat.

Many breast cancers are discovered in routine mammograms before any symptoms are present. However, not all breast cancers are detected by a mammogram, and not all women get mammograms or receive them often enough. So it is important for women to be observant of symptoms.

Doctors recommend that women become familiar with their breasts so they know how they normally feel. The following are cause for concern:

  • A new lump or mass: A hard, painless mass with irregular edges is more apt to be cancerous, but soft, rounded lumps and masses can also be breast cancer and may be painful
  • Breast swelling, all or part even with no lump present
  • Changes in the breast’s skin, such as irritation, redness, scale, dimpling and thickening
  • Fluid leaking from the nipple that isn’t breast milk
  • The nipple turns inward (nipple retraction)
  • Thickening of the nipple
  • Pain in the nipple and/or breast.

If a woman does detect a change or the appearance of one of the above symptoms, she should see an oncologist. Breast cancer can also be detected before symptoms occur, which is known as screening. Screening for breast cancer most often involves a mammogram.

Breast cancer treatments

Once breast cancer is diagnosed, oncologists will seek to determine the stage of the cancer, meaning the size and location of the cancer and how far it has progressed, either in the breast or to other parts of the body. Various scans and biopsies are used to pinpoint the stage of the breast cancer.

There are seven stages of breast cancer. The stage will help oncologists determine the type of treatment. Treatments for the first six stages have the goal of curing the cancer and keeping it from coming back. With the last stage, Stage IV, the goal is to improve symptoms and keep the patient alive, as Stage IV cannot be cured.

Five standard types of treatments are commonly used to fight breast cancer. Combinations of these treatments may be used. In addition, clinical trials test new ways to improve treatments and are sometimes available to patients.

Surgery

Most breast cancer patients undergo surgery to remove the cancer. Since the sentinel lymph node is the first place a cancer might spread, it is often removed and tested in the lab, giving an indication of the extent of surgery needed. Breast cancer surgeries include:

  • Breast conserving. Removes the cancer and some tissue around it. Also called lumpectomy or partial mastectomy.
  • Total mastectomy. Also called a simple mastectomy, this removes the entire breast that has cancer, and may involve removing some of the lymph nodes.
  • Modified radical mastectomy. Removes the entire breast affected by cancer, many of the lymph nodes, the lining covering chest muscles and possibly part of the chest wall muscles.
  • Radiation therapy.

This utilizes radiation, often high-energy X-rays, to either kill cancer cells or keep them from dividing (growing). External radiation is used to treat breast cancer and involves a machine that directs radiation to the cancer.

Chemotherapy

This is the use of chemicals to kill breast cancer cells or to impede or stop their growth. Systemic chemotherapy is the introduction of powerful chemical drugs into the entire body. This is the type of chemotherapy used to treat breast cancer and it can be administered into the blood stream by an injection or by oral medication.

Hormone therapy

By removing hormones or blocking the way they work, hormone therapy can stop cancer cells from growing. Several factors come into play when considering hormone therapy, and oncologists will discuss these with their patients.

Targeted therapies

Drugs, antibodies and other substances can be used to attack specific cancer cells while not harming normal cells nearby. Targeted therapies for breast cancer include monoclonal antibodies, cyclin-dependent kinase inhibitors and tyrosine kinase inhibitors.

Breast cancer treatment risks

There are a large number of potential risks from the treatment of breast cancer, from pain to heart problems to headaches and memory loss. Patients should discuss side effects and risks with their oncologist.

  • Surgical treatment carries the same risks as all surgeries, including, infection, blood loss, clotting, pain and reaction to anesthesia.
  • Radiation treatments can cause side effects of a rash on the skin, general fatigue, swelling of breast tissue and in rare cases damage to lungs or the heart.
  • Chemotherapy side effects depend on the drugs being used and may include hair loss, fatigue, susceptibility to infection, nausea and vomiting.
  • Hormone therapy side effects range from hot flashes, night sweats and vaginal dryness to risk of osteoporosis, blood clots and stroke.
  • Targeted therapies may carry side effects that depend on the substance used to target the cancer. These can include diarrhea, hair loss, nausea and heart problems.

Learn more about breast cancer screening and diagnosis

Breast Cancer Screening & Diagnosis