College of American Pathologists
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  Breast Cancer Information




Updated July 31, 2009

Breast cancer is the most common cancer among American women, except for skin cancers. The chance of developing invasive breast cancer at some time in a woman’s life is about 1 in 8 (12%). In 2009, an estimated 192,370 new cases of invasive breast cancer will be diagnosed among women in the United States.1

In addition to invasive breast cancer, there will be about 62,280 new cases of carcinoma in situ (CIS) in 2009. CIS is non-invasive and is the earliest form of breast cancer.2

A National Cancer Institute study found that 1 in 8 women will develop breast cancer in her lifetime. However, when breast cancer is diagnosed in the earliest, localized stage, the five year survival rate is close to 100%. So the earlier breast cancer is found, the better are the chances of successful treatment.

Breast cancer is a malignant tumor that develops from cells in the breast and is caused by uncontrolled growth of cells in the breast when cells in the breast lose their normal ability to control cell growth and rest. Most breast cancer is caused by genetic abnormalities that result from the aging process. The genetic abnormality may also be inherited.
The College of American Pathologists provides a free Internet-based service that reminds people to schedule annual health tests such as mammograms. Visit to select the day on which you would like to be reminded to schedule a mammogram. On that date, you will receive an e-mail reminding you to call your doctor or health care provider to schedule an appointment.

Having a regular high-quality mammogram in conjunction with a clinical breast exam is one of the most important things a woman can do to prevent breast cancer. Mammograms can help detect cancer before you can feel a lump in a self-exam, as well as cancers too small to feel during clinical breast exams.

The CAP agrees with the recommendations of the American Cancer Society that all women 40 years and older should have annual mammograms, based on their physician’s recommendation.

Women between the ages of 20 and 39 should have a clinical breast exam every three years. When they are 40 years old, they should begin having clinical breast exams every year. All women 20 and older should do a breast self-exam every month.

Risk factors
The exact cause of breast cancer is still unknown, but certain risk factors are linked to the disease.

Having a risk factor or several risk factors does not mean that you will get breast cancer.

The biggest risk factors are female gender and aging. Other risk factors include:

  • Family history: Having a mother, sister, or daughter with breast cancer nearly doubles a woman’s risk—but most women with breast cancer have no family history.
  • Personal history of breast cancer: Women with cancer in one breast have a higher chance of developing a new cancer in another part of the same breast or in the other breast.
  • History of breast biopsy: Certain types of abnormal breast biopsy results can be linked to a slightly higher risk for breast cancer.
  • Early onset and end of menstrual periods
  • History of radiation treatment: Women who had chest area radiation treatment as children or young women have a significantly increased risk for breast cancer.
  • White women are slightly more likely to develop breast cancer than are African-American women. African-American women are more likely to die of this cancer. At least part of this seems to be because African-American women tend to have more aggressive tumors, although why this is the case is not known. Asian, Hispanic, and Native-American women have a lower risk of developing and dying from breast cancer.

What happens during a mammogram?
A mammogram is an x-ray of the breast used to find breast changes in women who do not show any signs of breast cancer. Usually, two x-rays will be taken of each breast. Schedule your mammogram within two weeks after your menstrual period ends to make the procedure as comfortable as possible.

Tell your doctor if you are (or might be) pregnant or if you are breastfeeding. If you are pregnant, your doctor may recommend waiting until you deliver to have the mammogram to prevent exposing your developing child to radiation. If a woman is breastfeeding, the mammogram will also be postponed, because the milk makes it hard to examine the breasts.

The day of the mammogram, do not use any deodorant, perfume, powders or ointments on your breasts. These substances can leave a residue on your skin that may interfere with the x-rays.

Before the mammogram is done, remove any jewelry that could interfere with the x-ray and undress to the waist. You will be given a gown to wear while you take the test.

Mammograms are usually performed with the patient standing up, but, depending on the equipment being used, you may be asked to sit or lie down instead. One at a time, your breasts will be placed on a flat plate that holds the x-ray film. A second plate will be pressed firmly against your breast to help flatten the breast tissue. You may have to lift your arm or hold your other breast out of the way.

You will be asked to hold your breath while the x-ray is being taken, which only lasts a few seconds. Two pictures are usually taken of each breast, one from the top and one from the side.

The test takes about 10 to 15 minutes. You will probably have to wait about five minutes while the x-rays are developing in case repeat pictures have to be taken. Some clinics use digital imaging, and the pictures can be viewed right away on a computer screen.

Test results
The results of your mammogram are usually available in about 10 days. You may have to return for another mammogram if another view of a questionable area is necessary. Your mammogram will be classified as either normal or abnormal.

In a normal mammogram, no unusual growths, lumps or other types of abnormal tissue are seen. All of the glands that produce milk and the tubes in which milk flows (also called ducts) look normal.

In an abnormal mammogram, all areas of the breast tissue may not be seen clearly, and you will have to have another mammogram to get clear pictures of those areas. Most abnormalities found during a mammogram are not cancerous. An abnormal mammogram may also mean that an abnormal growth, lump or other type of tissue was seen. It may be cancerous (malignant) or non-cancerous (benign). Cysts (pockets of tissue filled with fluid) may also be seen.

An abnormal mammogram may show calcifications (bits of calcium). Tiny calcifications often occur in areas where cells are growing very rapidly, such as in a cancerous tumor. Larger calcifications are usually normal in women older than 50.

If your mammogram results are abnormal, you will have additional tests to determine if cancer is present.

What is a clinical breast exam?
A clinical breast exam is performed by a physician or other health care provider. It is most often performed in the same visit as your Pap test and pelvic examination. A yearly clinical breast exam is recommended for all women 40 and older. Women between the ages of 20 and 39 should have a clinical breast exam every three years.

During the examination, you will lie on your back and the doctor will examine your breasts for any changes in shape or size. The doctor will also gently feel each breast and examine the areas under both of your arms.

What is a breast self-exam?
Examine your own breasts once a month to check for any lumps. A monthly breast self-exam is recommended for women 20 and older. Ask your physician or health care provider to show you how to perform a breast self-exam.

The best time to do a breast self-exam is about a week after your period ends, so that your breasts are not swollen or tender. If you do not have regular periods, do your self-exam on the same day every month.

How to perform a breast self-exam
Lie down with a pillow under one shoulder and place your other arm behind your head.

Use the finger pads of the three middle fingers to feel for lumps in your breast. Press firmly enough so you know how your breast feels. It is normal to feel a firm ridge in the lower curve of each of your breasts.

Move around your breast in a circular pattern, in up-and-down lines, or in a wedge pattern (think of your breast as a pie and move in and out within each segment). Check your breasts the same way every time, be sure to check your entire breast area, and remember how your breast feels from month to month.

Repeat this procedure for the other breast.

Now stand and repeat the examination. Standing makes it easier for you to check the upper and outer parts of your breasts, which is where about half of breast cancers are found. You may find it easier to do the standing examination while you are in the shower. Some breast changes can be felt more easily when your skin is wet and soapy.

As an added safety measure, stand in front of a mirror after your self-exam to check your breasts for any skin dimpling, changes in your nipple, redness or swelling.

If you feel anything unusual, or notice any changes from previous months, see your doctor right away.

What if a lump is detected?
A new lump or mass in your breast is the most common sign of breast cancer. Not every lump is cancerous, but it’s important to have anything unusual checked by your doctor.

If you find a lump, or if something is detected on your mammogram, you will have other tests to find out if cancer is present. This may be another mammogram, or an ultrasound exam of your breast, another imaging test.

In addition to lumps, other signs of breast cancer include:

  • Swelling in part of the breast
  • Skin irritation or dimpling
  • Pain in the nipple or the nipple turning inward
  • Redness, itching or scaling of the nipple or breast skin
  • Discharge other than breast milk

What is HER2 Testing?
20 percent of patients with breast cancer have high levels of the HER2 gene and/or protein. In certain cases, HER2 Testing may be recommended by a physician. HER2 is a receptor (specialized protein) on the surface of breast cells and breast cancer cells that controls cancer cell growth, invasion, and spread of the cancer to other parts of the body. This testing can detect whether a breast tumor is HER2-positive, which tend to be higher risk cancers, and often respond differently to some types of treatment, such as certain types of chemotherapy or hormonal treatments.

What is a biopsy?
A biopsy is the only way to know for sure if you have breast cancer.

In a biopsy, cells are removed from your breast for a pathologist to examine under a microscope. There are several kinds of biopsies. A doctor may use a very thin needle to draw fluid and cells from a lump. Or you may need surgery to remove more tissue. Ask your doctor what kind of biopsy will be done and what you should expect during and after the procedure.

The pathologist will determine if any of the cells are cancerous, and if so, whether the cancer is invasive. The pathologist also identifies what kind of cancer is present. In the pathology report, the pathologist will give the biopsy a grade. In general, a lower grade number means a slower-growing cancer, while a higher number means a faster-growing cancer. The grade can help predict the patient’s prognosis—“how successfully the breast cancer can be treated.”


  1. American Cancer Society - May 2009
  2. Ibid


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