Breast Cancer Overview

Breast cancer occurs as normal cells in tissue start to grow and divide in an out of control manner. As they grow, the cells often, but not always, form a tumor in the breast that can be detected in a mammogram before it can be felt as a lump or thickening.

It is important to note that not all lumps in the breast are breast cancer, and not all breast cancers present with a lump. However, all lumps or thickenings in the breast need medical attention to determine whether they are one of many benign lumps that can occur in the breast or are truly a cancer.

Breast cancer is not a single disease; research evidence continues to indicate that there are a number of subtypes of breast cancer. They happen at varying rates in different groups and respond differently to treatments. Some are more aggressive than others and have very different long-term survival rates.

Common Breast Cancers

Breast cancer most often originates in the breast ducts that carry milk to the nipple.

These types, called ductal cancers, account for about 80 percent of all breast cancers. Lobular cancer begins in the glands (lobules) that produce breast milk and accounts for about 8 percent of all breast cancers.

When a cancer is confined within a breast duct or the cells of the lobules it is called in situ, meaning 'in site.' Cancers that break through the wall of a duct or the cells of the lobules and spread into the surrounding breast tissue are described as invasive or infiltrating breast cancers.

Other Breast Cancers

Inflammatory breast cancer is considered a rare but aggressive cancer that presents without a lump and results in the affected breast(s) having a swollen, red, or inflamed appearance.

Paget’s disease of the breast, which is also rare, involves the skin of the nipple and, usually, the darker circle of skin around the nipple.

Metastatic breast cancer, which is also known as stage IV breast cancer, is a cancer that begins in the breast and spreads to distant organs such as the brain, bones, lungs, and liver. About 6 percent to 8 percent of women and men are metastatic when first diagnosed. Metastatic cancer, when it occurs, is usually diagnosed months to years after being treated for an early stage cancer.

Who Gets Breast Cancer?

If you have breast tissue, you can develop a breast cancer. While primarily occurring in women, with 1 in 8 women in the United States developing an invasive breast cancer during her lifetime, men do get breast cancer too.

After skin cancer, breast cancer is the most frequently diagnosed cancer in women living in the United States; unfortunately, breast cancer death rates are higher than those for any other cancer, with the exception of lung cancer.

According to the National Cancer Institute, the incidence of breast cancer is highest in white women for most age groups, followed by African-American/black, Hispanic/Latina, Asian/Pacific Islander, American Indian/Alaska Native women.

African-American women have higher breast cancer incidence rates before 40 years of age, and higher rates of dying from breast cancer than women of any other racial/ethnic group in the United States at every age. Hispanic/Latina women tend to get breast cancer at a younger age than non-Hispanic white women.

Factors That Increase the Risk of Developing Breast Cancer

Aging: A woman’s chances of getting breast cancer increase as she ages.

Family History: A woman who has a mother, sister, or daughter diagnosed with breast cancer has double the risk of developing breast cancer than a woman who does not have a first-degree relative that was diagnosed with the disease. Note: About 85 percent of breast cancers occur in women who have no family history of breast cancer.

Genetics: Five percent to 10 percent of all breast cancers can be linked to women and men with gene mutations that were inherited from their mother or father. The BRCA 1 and 2 genes are the most common. Having either of these mutations substantially increases the lifetime risk of breast cancer. These mutations also carry an increased risk of ovarian cancer in women.

Dense Breasts: Women who have a high percentage of breast tissue that appears dense on a mammogram have a higher risk of breast cancer than women of similar age who have little or no dense breast tissue. Abnormalities in dense breasts, such as tumors, can be more difficult to detect on a mammogram.

Race: In the United States, breast cancer is diagnosed more often in white women and least often in Alaska Native women.

Behaviors That Increase the Risk for Developing Breast Cancer

Weight: Studies have found that the chance of getting breast cancer is higher in postmenopausal women who have not used menopausal hormone therapy and who are significantly overweight compared to peers who are of a healthy weight.

Smoking: Researchers at the American Cancer Society found an increased risk for breast cancer among women who smoke, especially those who started to smoke before having their first child.

Alcohol: The National Cancer Institute reports that over 100 studies document an increased risk of breast cancer associated with alcohol consumption. 

Inactive Lifestyle: Women who are physically inactive throughout life may have an increased risk of breast cancer.

What Should You Know to Lower Your Risk of Breast Cancer?

Breast Cancer Symptoms

Remember that noticing these symptoms may not mean that breast cancer is to blame. That said, if you are experiencing any, it's important to bring them to your doctor's attention.

  • A breast lump
  • Breast pain: That said, breast cancer is usually painless during its early stages. Pain in the breast can be caused by a number of different non-cancerous breast conditions.
  • A noticeable change in the size or shape of a breast
  • Dimpling of skin on part of the breast (like an orange peel)
  • Redness or a rash-like appearance to the skin on the breast: It may resemble mastitis, an infection in the breast, which usually affects women who are breastfeeding.
  • Flaky or crusty looking skin around the nipple
  • Inward turning nipple
  • Nipple discharge (perhaps with blood)

How Breast Cancer Is Diagnosed

A routine mammogram or the results of a physical exam may indicate something suspicious for breast cancer. The only way to confirm a diagnosis of breast cancer is to do a biopsy and take a sample of the tissue from the area in question. The sample needs to be examined under a microscope by a pathologist who is a medical doctor to check for cancer cells. If cancer cells are found, the pathologist will assess the characteristics of the cancer and write a report on the findings.

The type of biopsy you get depends on several factors, including the tumor's size and location, and how concerned your doctor is about it. Options include:

  • Fine Needle Aspiration: The procedure is performed by a breast surgeon or radiologist using a thin needle with a hollow center to extract a sample of cells from the area in question.
     
  • Core Needle Biopsy: This type of biopsy uses a larger hollow needle than one used in a fine needle aspiration to remove tissue samples.
     
  • Surgical Biopsy: During this biopsy, the surgeon uses a scalpel to cut through the skin to remove a piece of the tissue in question to be examined by the pathologist.  

Explore our Breast Cancer Diagnosis section for more in-depth information on tests and screenings.

How Breast Cancer Is Treated

While there are several options for the treatment of breast cancer, the kind and amount used for a particular case is determined by the type of cancer and extent to which it has spread. Usually, a woman or man diagnosed with breast cancer will receive more than one treatment.

  • Surgery: Most breast cancer patients have surgery to remove their cancer. Those with an early breast cancer often have the option of having breast conserving surgery to remove the lump and a margin of tissue surrounding the lump. This surgery is usually followed by radiation therapy.
     
  • Chemotherapy: When treatment requires a systemic approach to kill cancer cells that may have traveled beyond the breast or to shrink tumors prior to surgery, patients are treated with chemotherapy, which are special drugs that are taken in pill form or administered into a vein.
     
  • Hormonal Therapy: An oral medication that blocks cancer cells from getting the hormones they need to grow. It is frequently given to women and men following active treatment to prevent a recurrence.
     
  • Biological Therapy: Treatment that helps a patient’s immune system fight cancer cells.
     
  • Radiation Therapy: This treatment uses high-energy rays to kill cancer cells. The treatment is usually administered Monday through Friday for several weeks. Treatments are brief and painless.

Our Breast Cancer Treatment section delves into each of these in greater detail, and it's a great place to start if you're exploring options.

Early Detection and Intervention

Finding and treating breast cancer while it is still an early stage cancer, before it spreads beyond the breast and through the lymphatic system, offers the best possible prognosis.

Women and men with an early stage cancer are often candidates for breast conserving surgery, such as a lumpectomy, and may not need to have chemotherapy treatments.

Early detection requires:

  • Knowing what your breasts normally look and feel like, and reporting any changes or symptoms to your physician
  • Seeing your physician annually for a comprehensive breast exam
  • If you are under 40 years of age and have a family history of breast cancer, speaking with your physician as to when you need to begin annual mammograms and discuss the need for genetic counseling
  • If you are over 40 with no family history of breast cancer, getting regular mammograms. Note: Mammograms can detect a breast cancer years before it can be felt, while it is easier to treat.

A Word from Verywell

There are more than 3 million of us in the United States today that once heard the words, "You have breast cancer." We are living proof that breast cancer can be successfully treated. When breast cancer is caught at an early stage, it can be treated more conservatively and result in a shorter recovery time.

Sources:

American Cancer Society. What is Breast Cancer? Medical Review: 09/25/2014. Revised: May 4, 2016.

Centers for Disease Control. Risk Factors for Young Women. Reviewed: March 13, 2014  Updated: March 13, 2014.

National Cancer Institute. A Snapshot of Breast Cancer. Posted: November 5, 2014.

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