Defined as a cancer that forms in the cells of the breasts, breast cancer is the most common cancer in American women, except for skin cancer. While occurring infrequently in men, breast cancer is diagnosed in a U.S. woman, on average, every two minutes and now accounts for 30% of all new cancer diagnoses in women in the nation.

Yet, the disease differs based on age and race/ethnicity, placing a heavy toll in lives lost and human suffering. According to the latest statistics:

  • About one in eight U.S. women (12%) will develop invasive breast cancer over the course of her lifetime.
  • Currently, there are more than 3.8 million women with a history of breast cancer in the U.S. This includes women currently being treated and women who have finished treatment.
  • In 2020, an estimated 276,480 women will be diagnosed with invasive breast cancer in the U.S. while about 42,170 women are expected to die from the disease.
  • About 85% of breast cancers occur in women with no family history of the disease. Another 5% to 10% can be linked to gene mutations inherited from one's mother or father.
  • Although breast cancer rates are slightly higher among white women than black women, black women are more likely to be diagnosed with breast cancer at later stages of the disease, experience delays in treatment of two or more months after diagnosis, and are 42% more likely to die of their cancer.
  • African American women also have higher rates before age 40 and are nearly twice as likely as white women to be diagnosed with triple negative breast cancer, which is more aggressive and harder to treat than other types of breast cancer.
  • Among Hispanic women, breast cancer is the leading cause of cancer death. They are also less likely than whites to be diagnosed with breast cancer at a localized stage.

Signs and Symptoms

The most common sign of breast cancer is a new lump or mass in the breast. It is most likely to be a hard mass that has irregular edges and is usually painless. However, breast cancers can be tender, soft or round and painful.

Other symptoms include:

  • Breast or nipple pain
  • Nipple retraction (turning inward)
  • Nipple discharge other than breast milk
  • Nipple or breast skin that is red, dry, flaking or thickened
  • Skin dimpling (sometimes looking like an orange peel)
  • Swelling of all or part of a breast (even if no lump is felt)
  • Swollen lymph nodes under the arm or around the collar bone

Types of Breast Cancer

Breast cancer is not a single disease. Rather, there are many forms based on where the tumor starts in the breast tissue and whether the cancer has spread or not. In situ breast cancer (where abnormal cells remain in the place where they formed) starts in a milk duct and has not spread throughout the breast. Invasive breast cancer has spread into surrounding breast tissue.

The most common forms of breast cancer are:

  • Ductal carcinoma in situ
    According to the American Cancer Society (ACS), one in five new breast cancers are "ductal carcinoma in situ" (DCIS), meaning the cells are cancerous but have not spread to surrounding tissue. DCIS is an early stage cancer that starts in a milk duct and is noninvasive. Nearly all women with DCIS can be cured with either breast-conserving surgery (removing the tumor and treating the breast with radiation) or a simple mastectomy.
  • Invasive ductal carcinoma
    In 2020, the ACS estimates that more than 276,000 women will be diagnosed with breast cancer that has spread into the surrounding breast tissue (invasive) and possibly other parts of the body. Of these cancers, about eight in 10 are "invasive ductal carcinomas" (IDCs). This type starts in the cells that line a milk duct in the breast. Over time, IDCs can spread to the lymph nodes and possibly to other parts of the body.
  • Invasive lobular carcinoma
    Accounting for 10% to 15% of breast cancer cases, "invasive lobular carcinoma" (ILC) is the second most common form of invasive breast cancer. ILC starts in the milk-producing glands (lobules) and can spread to other parts of the body.

Rare types of breast cancer include inflammatory breast cancer (1% to 5% of all breast cancers), Paget disease of the breast (1% to 3% of all breast cancers) and angiosarcomas (less than 1% of all breast cancers).

Breast cancer cells are tested to see if they have certain proteins that act as receptors for tumor cells to grow and divide. Knowing your breast cancer subtype is important for knowing your treatment options. The main subtypes are:

  • Hormone receptor positive or negative
    Some breast cancer cells have proteins in or on cells called "hormone receptors" (HR) that attach to estrogen or progesterone, causing the cells to depend on these hormones for growth.

    Because HR-positive breast cancer cells need estrogen and/or progesterone to grow, this subtype can be treated with drugs that lower hormone levels or block the hormone receptors. In contrast, cancer cells that do not have hormone receptors are classified as "hormone-receptor negative" and will not be affected by treatments aimed at blocking estrogen or progesterone. Typically, HR-negative cancers grow faster than HR-positive tumors.
    • Estrogen receptor positive (ER+): An estimated 80% of all breast cancers are estrogen-receptor positive (ER+) and need estrogen to grow.
    • Progesterone receptor positive (PR+): Of the breast cancers that are estrogen-receptor positive, about 65% are also PR-positive and grow in response to progesterone.
  • HER2 positive or negative
    HER2 (human epidermal growth factor receptor 2) is a growth-promoting protein on the outside of all breast cells. Normally, this protein helps breast cells grow, divide and repair themselves. However, sometimes things go wrong in the gene that controls the HER2 protein. As a result, in about 20% of breast cancer cases, the cancer cells make too much HER2 protein, causing breast cancer cells to grow and divide in an uncontrolled way.

    Cancer cells that are HER2-negative have little or no HER2 protein and are less likely to spread to other parts of the body. HER2-positive cancers tend to be fast-growing and aggressive and are treated with therapies that target the HER2 protein.
  • Triple negative breast cancer
    When developing therapies used to help destroy cancer, scientists think of a tumor cell as a house and the three most common receptors known to fuel the cell's growth — estrogen, progesterone and the HER2 protein — as the locks on the front door. If your cancer tests positive for one of these receptors, then oncologists can use a targeted therapy as the key to get inside the cancerous cell and destroy it. With triple-negative breast cancer (TNBC), however, the tumor cells test negative for all three receptors, so the keys (drugs that target estrogen, progesterone and HER-2) are largely ineffective.

    Considered a rare cancer, TNBC accounts for roughly 10% to 15% of all breast cancers and differs from other types of invasive breast cancer because it grows and spreads faster, has a worse prognosis and is usually a cell type called "basal like" that tends to be a more aggressive, higher grade cancer. While TNBC affects women and men of all races and ages, it is approximately twice as common among Black women. Among Black women who develop breast cancer, there is an estimated 20% to 40% chance of the breast cancer being triple-negative. TNBC is also more common in women under age 40 and those with a BRCA mutation. About 70% of breast cancers diagnosed in people with an inherited BRCA mutation, particularly BRCA1, are triple-negative.


Health care providers use several tests to detect breast cancer and confirm a diagnosis. The most widely used tests are:

  • Mammograms
    Mammograms use low-dose X-rays to find breast cancer. Overall, the sensitivity of mammography is 87%, meaning mammograms correctly identify about 87% of women who have breast cancer. Besides the two-dimensional (2D) mammogram where two X-rays are taken — one from the top and a second from the side — there are now three-dimensional (3D) mammograms, which collect multiple images of the breast from several angles.

  • Breast ultrasound
    In an ultrasound, a wand that gives off sound waves is guided over the breast to take pictures of the inside of the breast. A recent study found that adding ultrasound to mammography can increase breast cancer detection rates by 1.9% to 4.2%.

  • Breast MRI
    Breast MRI (magnetic resonance imaging) uses radio waves and strong magnets to make detailed pictures of the inside of the breast. Recent research shows that breast MRI can locate small breast lesions sometimes missed by mammography.

  • Breast biopsy
    When imaging tests find areas in the breast that could be signs of cancer, a physician will perform a biopsy to find out for sure. During a biopsy, the doctor removes small pieces of tissue from the suspicious area that are looked at in the lab to see if they contain cancer cells.

Tests Used to Find Out if Breast Cancer Has Spread

If your oncologist suspects that your cancer has spread beyond the breast and nearby lymph nodes, he or she may order imaging tests to confirm the diagnosis and help determine your course of treatment. Tests that may be done are chest X-rays, CT scans, MRIs, ultrasounds, PET (positron emission tomography) scans and bone scans.

Insurance Coverage

Breast cancer screenings and diagnostic tests are expensive, but there is good news: Under the Affordable Care Act (ACA) and many state laws, private insurance plans as well as Medicare and Medicaid must cover the cost for breast cancer screenings, including genetic testing and preventive drug therapy. By law, reconstructive procedures, as are used after a mastectomy, are always covered. This is not the case for diagnostic tests, however, where insurers may require a co-pay and other fees. Here is an update.

No-Cost Coverage for Screening and Prevention

Private health insurance companies base their coverage policies for breast cancer screenings and prevention services on guidelines from the United States Prevention Services Task Force — an independent panel of national experts in disease prevention — and the Health Resources and Services Administration, a federal government agency that is part of the Department of Health and Human Services.

Under these guidelines, private insurance plans and state Medicaid programs must cover these services at no cost to women:

  • Screening mammogram at least every two years and as often as every year for women ages 40 to 74 with average risk for breast cancer
  • Genetic counseling and testing for mutation of the BRCA1 and BRCA2 genes in some women with a personal or family history breast, ovarian, fallopian tube, or peritoneal cancer
  • Preventive drug therapy for women ages 35 and above with elevated risk of breast cancer

Coverage for Diagnostic Tests

When it comes to diagnostic tests for breast cancer, insurers can require a co-pay and other fees, depending on the health plan. This is why it is important to know the terms of your health insurance and talk to your health care team. They usually know who can help you find answers to your questions about coverage for your diagnostic tests.

The American Cancer Society recommends these resources if you need help managing the costs of your diagnostic tests and breast cancer treatment:

  • Patient Access Network Foundation (PANF)
    Toll-free number: 1-866-316-7263; www.panfoundation.org
    Helps under-insured patients cover out-of-pocket costs
  • Patient Advocate Foundation (PAF)
    Toll-free number: 1- 800-532-5274; www.patientadvocate.org
    Works with the patient and their insurer to resolve insurance problems

Surgical Options and Decision-Making

A treatment plan for breast cancer is determined by the surgeon or oncologist in partnership with a woman and her loved ones. Because surgery remains the primary treatment for breast cancer, one of the first decisions most women will make after a breast cancer diagnosis is the type of surgery to remove the cancer.

There are many surgical options depending on your goals and preferences and the cancer itself. Because every breast cancer is different, the type of surgery will depend on these factors:

  • The type of cancer
  • The location of the tumor in the breast
  • The size of the tumor
  • Whether the cancer has spread
  • How abnormal the cells look under a microscope (the grade)
  • Whether the cancer has hormone receptors for targeted cancer drugs
  • Whether you have gone through menopause
  • Whether you have been previously treated for breast cancer

Based on these factors, your doctor will make recommendations about surgical options so you can make a decision that is best for you.

Surgical Options

There are two main types of surgery to treat (remove) breast cancer:


Also known as "breast-conserving surgery," a lumpectomy involves removing the part of the breast where the tumor is located and a border of healthy tissue around the cancer to get clean margins. The surgeon may also remove part of the chest wall lining if the cancer is near it or remove some lymph nodes under the arm for biopsy. If the biopsy indicates the margins also have cancer, a re-operation or mastectomy may be necessary. Lumpectomy may be a good choice if you have a noninvasive breast cancer or a less advanced stage of cancer. However, in most cases, women opting for a lumpectomy also have radiation therapy to the breast and sometimes the underarm area.

  • Oncoplastic reduction lumpectomy is a procedure where a larger amount of breast is removed during the lumpectomy, and the breast is re-shaped smaller. This procedure allows the woman to get a breast reduction and the benefit of a larger lumpectomy. After this surgery, women still need radiation therapy.

Mastectomy is an operation to remove the entire breast and is typically done if a woman has more advanced breast cancer, has small breasts but a big tumor in one of the breasts or has a genetic mutation for inherited breast cancer.

There are different types of mastectomy, including:

  • Total (simple) mastectomy is the removal of the entire breast with the nipple and surrounding skin. Some of the lymph nodes under the arm may also be removed. This can be done with or without reconstruction at the time of surgery.

  • Modified radical mastectomy is the removal of the entire breast with the nipple and surrounding skin and the lymph nodes under the arm. A reconstruction can be done at the time of surgery.

  • Radical mastectomy is the removal of the entire breast, the overlying skin, chest wall muscle and the lymph nodes under the arm. This procedure is rarely done any more.

  • Nipple sparing mastectomy involves removing the breast tissue and preserving the nipple and areola. This is usually done with reconstruction at the time of the procedure.

  • Double mastectomy, also known as bilateral mastectomy, is the removal of both breasts. Typically, doctors only recommend a double mastectomy if there is cancer in both breasts or the woman carries the BRCA1 or BRCA2 gene or is at higher risk of developing breast cancer for any reason.

Making the Decision About Mastectomy

Of the estimated one in eight American women who will develop invasive breast cancer during her lifetime, about two-thirds (64.5%) will choose a lumpectomy to remove the breast section that contains the tumor. This leaves more than one in three women (35.5%) who opt for a mastectomy to remove the entire breast to treat their cancer.

Lumpectomy and mastectomy procedures are both effective treatments for breast cancer. In fact, research shows the same survival rate with lumpectomy plus radiation therapy and mastectomy.

More than 100,000 women in the U.S. choose mastectomy each year, especially women younger than 40 and those with larger and/or more aggressive tumors. One reason is to reduce their risk of the cancer coming back (recurrence) if the entire breast is removed. Other reasons women opt for a mastectomy include not wanting to undergo radiation therapy or the opportunity to rebuild the shape and size of their breast through reconstruction, often at the time of mastectomy.

Because the decision is very personal, experts recommend discussing your surgical options with your breast specialist based on your breast cancer features, your medical history and your personal preferences or concerns. It is also a good idea to get a second opinion before making a final decision and discussing reconstructive surgery options with a breast surgeon and a plastic surgeon if your choice is a mastectomy. This will give you time to plan when to have the reconstruction and to understand the steps involved before the surgery.


In addition to surgery, other treatment options may be used before or after surgery.

  • Chemotherapy
    Chemotherapy is the use of drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing and making more cells. Chemotherapy may be one drug or a combination of drugs.
  • Hormone therapy
    Hormone therapy works by blocking or lowering the level of hormone from getting to cancer cells, which the cancer needs to grow.

  • Targeted therapy
  • By focusing on a specific gene or protein, these treatments attach to a specific target and block the growth and spread of cancer cells while limiting damage to healthy cells. As such, targeted therapies cause fewer and less severe side effects than chemotherapy.

  • Immunotherapy
  • Immunotherapy is the use of drugs that target proteins on immune cells, called "checkpoints," that need to be turned on or off to trigger an immune response against the breast cancer cells.

  • Radiation therapy
  • As with surgery, radiation therapy may be used to shrink or slow tumor growth.

This resource was created with support from Daiichi Sankyo, Merck and Sanofi Genzyme.

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