Facts on Mammograms

  • A mammogram is an X-ray examination of the breast used to screen for early breast cancers.
  • The benefits of mammography outweigh the small risks associated with the radiation exposure; radiation exposure in a mammogram is less than that obtained on a transcontinental flight.
  • Physician groups differ in their specific recommendations for mammogram screening guidelines, including the age at which women should begin having mammograms.
  • The mammogram is a quick procedure and involves mild discomfort as the breasts are compressed for a few seconds to obtain the image.
  • The ability of the mammogram to detect abnormalities is reduced in women with breast implants.
  • Screening mammography has been shown to significantly reduce deaths from breast cancer.

What is a mammogram?

A mammogram is a special X-ray examination of the breast made with specific X-ray equipment that can often find tumors too small to be felt. A mammogram is one of the best radiographic methods available today to detect breast cancer early. It can detect most cancers at least a year before they can be felt by the doctor or patient herself.

A woman may experience significant distress, anxiety, and fear associated with the mammogram and with the prospect of discovering a tumor. However, the procedure itself is relatively simple. Most breast disorders are not cancer, and even in the remaining number of cancer cases, more than 90% are curable, if detected early and promptly treated.

Although mammograms, like many other medical tests, are not 100% accurate, scheduling a regular mammogram represents the best radiological way to find breast changes early before there are any obvious signs or symptoms of cancer. Several studies show that mammogram can reduce breast cancer deaths by more than a third.

History of mammograms

Mammography started in 1960, but modern mammography has existed only since 1969 when the first X-ray units dedicated to breast imaging were available. By 1976, mammography as a screening device became standard practice. Its value in diagnosis was recognized. Mammography continues to improve as lower doses of radiation are detecting even smaller potential problems earlier.

When should I get a screening mammogram?

Early screenings through mammography and specialized training of breast radiologists are allowing doctors to detect early breast cancer when treatment can be most successful.

Mammography may detect over 85% of breast tumors, and results are still better if the screening is conducted along with a physical examination. It is clear that screening women older than 50 years reduces the number of deaths from breast cancer. However, in women younger than 50 years, breast X-ray screening offers a very small, if any, benefit. Doctors don't always agree on when to have a baseline mammogram or who should be screened and when, and guidelines from reputable medical societies differ in their recommendations:

  • The US Preventive Services Task Force recommends against routine screening of women under age 50 and screening mammography every 2 years from ages 50-74.
  • The American Cancer Society issued new guidelines in October 2015 about mammography, stating that most women should begin yearly mammograms at age 45, and at age 55 start having mammograms every other year.
  • The American Congress of Obstetricians and Gynecologists and the American College of Radiology recommend annual screening mammograms starting at age 40.

A discussion with the patient's primary care doctor about when the patient should get routine screening is helpful to clear confusion about annual mammogram screening because of the disparity in recommendations. It is a real advantage to diagnose breast cancer at an early stage, in a phase in which it is possible to remove a small part of the breast only, with high likelihood of cure.

Women with a personal or family history of breast tumors must work with their physicians to develop a screening program appropriate for the individual situation. However, breast tissue in younger women (younger than 30 years) tends to be denser, and this makes it more difficult to detect small changes in the breast on a mammogram.

How do I prepare for a mammogram?

  • Fasting is not necessary the day of the test, nor do you have to observe any particular dietetic rules in the days before a mammogram. In some women, caffeine-containing products (such as coffee, cola, and chocolate) could make the breasts more tender and thus the test more uncomfortable. For this reason, women who are sensitive to caffeine may choose stop caffeine consumption for two weeks before the test.
  • The phase of the menstrual cycle does not affect the quality of the images; however, it is better to perform a mammogram when a woman's breasts are not painful. Avoid the preovulatory and postovulatory period (half cycle) and premenstrual period. If a woman is still having menstrual cycles, she may find it more comfortable to have a mammogram 1 to 2 weeks after her period, when her breasts tend to be less tender.
  • It is preferable to wear two-piece clothing, such as pants and a top, to simplify undressing for the mammogram.
  • In the hours before the test, avoid applying cosmetics, oils, creams, and especially talc or deodorant.
  • Give the radiologist any information about previous mammograms for comparison, even if they were performed in other medical centers. You can request that these results be sent before you have a mammogram.
  • Because breast tissue changes during a woman's life, the radiologist may not consider a mammogram useful for certain women. The density of breast tissue in younger women often makes a mammogram very difficult to interpret. In fact, as women age, some changes occur in the structure of the breasts: glandular and fibrous tissues reduce in size, and breast tissues become more fatty. These changes modify the clarity of the mammogram, making it much clearer in older women where breast cancers are more easily "seen" by mammograms.

What happens during the mammogram procedure, and will it hurt?

The mammogram is a quick and easy procedure that only takes only a few seconds. Some women experience mild to moderate discomfort as the breasts are compressed for a few seconds to obtain the image.

  • You will be asked to remove all clothing above the waist including jewelry and metal objects from around the neck.
  • Then you will simply stand in front of an X-ray machine. The radiology technician places the breast between two plastic plates. The plates lightly press the breast and make it flat just enough so breast tissue can best be seen on the mammogram. This compression may be uncomfortable for a few seconds, but it helps to improve the quality of the mammographic image. Pressing the breasts for a few seconds is not harmful and minimizes the necessary X-ray dose.
  • The technician will take two X-rays of each breast (and reposition you) for a complete view of the entire gland. Each breast has a double scan. In the craniocaudal projection, the X-rays beam from above toward the radiologic film positioned under the breast. In the mediolateral projection, X-rays come from the inner side toward the outside of the breast.

What are the different types of mammograms?

Women without a history of breast problems usually have a screening mammogram performed. For women with a history of breast problems, a targeted mammogram may be performed to better evaluate a particular area of the breast. Sometimes special mammograms may be requested by your doctor.

  • Diagnostic mammogram: If results of a screening mammogram are unclear, abnormal, or if additional images are desired, the woman is asked to return for a diagnostic mammogram, which consists of additional images than those taken in the screening mammogram.
  • Ductogram: If additional views are needed for specific reasons, such as bloody discharge from the nipple, the doctor may request a ductogram. It consists of mammography performed after a fine plastic tube is placed into the opening of the duct into the nipple and a small amount of dye is administered.
  • Pneumocystography: This mammography is performed after a cyst is emptied with fine-needle aspiration and core biopsy, usually after the cyst has been seen on an ultrasound or if the cyst can be felt.
  • Stereotactic mammography: Based on mammograms taken from two angles, a computerized map shows the precise location of masses or calcifications. This technique allows, after local anesthesia, a metallic wire with a little hook at the end to be inserted into a breast lump. The wire then guides the surgeon during surgery to remove the tumor and the surrounding healthy tissue completely. After removal, a new film of the breast is taken to ensure that all the suspicious tissue has been removed. However, a stereotactic biopsy may be performed in which a small computer-controlled system guides the placement of a needle into the lesion or lump for sampling in a laboratory.
    • Two instruments have been developed to obtain stereotactic breast biopsies: the mammotome and the advanced breast biopsy instrument (ABBI). Both instruments use a rotating knife that cuts the tissue samples from the rest of the breast. Each type of biopsy has distinct advantages and disadvantages, but their accuracy is similar if well performed.

Other procedures are in limited use and some are undergoing clinical trials. These mammography procedures are used to improve the diagnostic accuracy of mammograms and are as follows: 3D mammography, MRI mammography, positron emission tomography (PET scan mammography), and diffuse optical tomography (light instead of X-rays produce the mammogram). Each specialized test has advantages and disadvantages; the radiologist who does the test can explain the need for such a new test.

How will I receive the results of my mammogram?

Ask your health-care professional or radiologist how the results of your mammogram will be communicated to you.

If your mammogram results are normal

If the mammogram appears clearly normal, no further tests are needed. Most breast changes are not malignant, and most women will have no breast cancer detected during a regular mammogram screening.

Sometimes the radiologist will request an additional diagnostic mammogram or an ultrasound study of the breast, which never is a substitute for, but always complements, the views taken with a mammogram.

If your mammogram results are abnormal (not normal)

Sometimes a woman could be recalled after a few days because the radiologist simply wants to be sure the breast images are the best possible and for a better evaluation of certain areas of the breast. In such cases, special mammographic tests may be performed.

  • If cancer is found, a number of treatment options, including surgery, radiotherapy, hormone treatment, and chemotherapy are available. The treatment option must be based on the individual woman and the type and size of breast cancer present.

What diseases or disorders can mammography diagnose?

  • Any suspicious area on a mammogram will be magnified and examined. The radiologist reading the mammogram will consider all views taken. Generally, if the radiologist can see defined margins in a suspicious area, they may indicate a benign or harmless lesion. If they are undefined, the mammogram may indicate a malignant or cancerous lesion. Obviously, the experience of the doctor who evaluates the mammogram is fundamental in order to distinguish the benign lesions from the malignant ones.
  • A mammogram could show white spots called - according to their size - calcifications and microcalcifications. The first are small deposits of calcium salts that occur in the breasts for many reasons. The second are very tiny and can be scattered throughout the breasts or gathered in small clusters and are normally due to aging or noncancerous causes (for example, from aging of the breast arteries, old injuries, or inflammations). Most of them are of no concern.
    • Suspicious microcalcifications must be evaluated further, and the doctor will consider their number, size, and where they are located, among other characteristics. Sometimes calcifications can indicate the presence of early breast cancer, but usually they just indicate the presence of tiny cysts.
    • If some microcalcifications are present on a mammogram, the woman may be asked to return for further assessment and use of special X-rays, which magnify the concerned area of the breast.

Do I need to follow-up with my doctor after my mammogram?

If your mammogram is normal, you can wait to have another mammogram at the interval that your doctor has recommended. If you experience any problems with your breasts or changes in the breasts such as a breast lump, breast pain, nipple thickening or discharge, or a recent change in breast size or shape, must be evaluated by a physician. You should always mention anything suspicious to your doctor.

  • To help diagnose breast disease, the doctor will take a medical history that will include questions on your general health, symptoms and their duration, age, menstrual status, number of prior and actual pregnancies, drugs taken, and relatives with benign breast conditions or breast cancer.
  • During the physical exam, the doctor will look carefully at your breasts both while you are sitting and lying down. You will be asked to raise the arms over the head or let them hang by the sides. The doctor will check the breasts for any changes in the skin, any discharge from the nipples, or any difference in appearance between the two breasts. Then, using the pads of the fingers looking for lumps, the doctor examines the entire breast, the underarm, and the collarbone area.

What are the risks of mammogram screening?

The benefit of mammography screening outweighs the risk of any harm from the radiation. Currently it is estimated that ionizing radiation needed for a mammogram is lower than the dose of cosmic radiation to which a passenger on an intercontinental flight may be exposed, or a skier on a mountain over 3,000 meters. Use of low-dose radiation gives doctors the ability to repeat the mammogram once a year, beginning after age 40 to 50 years. A mammogram could be prescribed for women with personal or family history of cancer of the breast or other organs, regardless of her age.

Those patients who have not entered menopause need to make sure they are not pregnant before obtaining a mammogram due to the small potential radiation exposure.

For women who have a breast implant, there is an extremely small chance that the pressure placed on the implant during the mammography will cause a rupture or break. If this occurs, a surgical operation may be needed to have the implant replaced.

In a small number of cases, the accuracy of the mammogram is lower than usual.

  • For women with breast implants, the ability of mammography to detect abnormalities is reduced because the content of the implant (a gel or a liquid) may block the view and because the scar tissue surrounding the implant tightens. Additional X-ray views may be required, and other imaging tests such as MRI may be required in this population.
  • False-positive readings on a mammogram occur when cancer is not present, but a mammogram is read as abnormal. Most of these false-positive readings will turn out not to be cancer. At all ages, 5% to 10% of mammograms are abnormal and are followed up with additional testing (a fine-needle aspiration [or sampling], surgical biopsy, or ultrasound).
  • False-negative findings occur when mammograms appear normal even though breast cancer is actually present and are more common in younger women than in older women. Currently, the rate of false-negatives in mammography is around 8% to 10%.

What are the risk factors for breast cancer?

  • Age: Risk increases with age. Seventy-seven percent of women with breast cancer are older than 50 years at diagnosis; women aged 20 to 29 years represent less than 0.4% of the total.
  • Genetics: Around 5% to 10% of breast cancers result from inherited mutations. Sixty to seventy percent of women with mutations of BRCA1 and BRCA2 genes will develop a breast cancer by age 70 years. Also mutations of the p53 gene increase the risk. In addition, some families without gene mutations have multiple family members in multiple generations with breast cancer. Women from such families are at an increased risk for developing breast cancer.
  • Family history: Women who have a first-degree relative (sister, mother, or daughter) with breast cancer double the risk, and those who have two affected relatives multiply the risk three times.
  • Medical history: A previous breast cancer increases risk (3 to 4 times) of developing a cancer in the same breast or in the opposite side.
  • Fibrocystic breast disease does not increase the risk, but a type of microscopic change known as atypical hyperplasia of the breast tissue does confer an 3 to 5 fold increased risk.
  • Previous therapeutic irradiations always cause a meaningful increase in risk.
  • Menstrual cycles: Early onset of menstruation (before age 12 years) or late menopause (older than 55 years) or both slightly increases risk.
  • Pregnancies: No pregnancy, or first pregnancy after age 30 years, increases risk moderately.
  • Hormone therapy (HT) for menopause: Combination hormone therapy with estrogen and progesterone increases the risk of breast cancer, but the risk is returns to normal five years after stopping the therapy. HT with estrogen alone does not appear to increase risk.
  • Oral contraceptive use may slightly increase breast cancer risk, though this remains controversial.
  • Breastfeeding: According to some studies, breastfeeding for 1 1/2-2 years reduces risk.
  • Alcohol: High consumption of alcoholic beverages increases risk.
  • Smoking: There is some evidence that smoking may increase risk.
  • Obesity: Being overweight increases risk.
  • Physical activity: Movement and daily activity reduce risk and are therefore useful.

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BRCA Genes and Your Breast Cancer Risk

Medical Author: Melissa Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

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Only about 5% of women with breast cancer are found to carry a mutated BRCA gene. Studies have confirmed that women who carry these BRCA mutations have a high risk for development of breast cancer, about five times that of women who do not have BRCA gene alterations. Overall, around 12% of all women will get breast cancer during their lifetime; in contrast, around 60% of women with a BRCA1 or BRCA2 mutation will get the disease. Having a BRCA mutation also predisposes a woman to developing breast cancer at an early age (before menopause). The incidence of BRCA mutation is higher in some ethnic groups, such as people of Ashkenazi (European) Jewish origin and in some populations in Iceland, the Netherlands, and Norway.

Men who carry one of the BRCA mutations also have an increased risk for breast cancer.

BRCA mutations also increase the risk of ovarian cancer. About 1.7% of women in the general population get ovarian cancer as compared with 15% to 40% of women with BRCA1 or BRCA 2 mutations....

Medically reviewed by Wayne Blocker, MD; Board Certified Obstetrics and Gynecology

REFERENCES: Mammograms.

Siddique, M. N. MBBS. "Mammogram Guidelines." Dec 12, 2014.

Dongola, N. MD. "Mammography in Breast Cancer." Medscape. May 19, 2015.

American Cancer Society. "American Cancer Society Releases New Breast Cancer Guideline." Oct 20, 2015.