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Decision Making Tool: Should I Have a Mammogram?

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What Are the Potential Benefits of a Mammogram? | What Are the Potential Risks and Limitations of a Mammogram? | Can It Improve Your Health? | Expert Advice | Putting the Pieces Together

mammogram.gifA mammogram is a screening test for breast cancer. These types of screening tests play an important role in maintaining good health. While some tests can be done quickly during a regular doctor’s visit, a mammogram requires an additional appointment at a special facility. The test itself is also rather uncomfortable, not to mention the stress that just the mention of cancer can cause. Do the benefits of mammograms outweigh these downfalls? The following will help you understand the benefits and risks of a mammogram so that you can make an informed decision about your options.

What Are the Potential Benefits of a Mammogram?

Screening tests can help identify illnesses and health problems before symptoms arise. For illnesses like cancer, early detection may allow for more treatment options and can improve the prognosis.

Mammograms can suggest changes in the breast that may be cancerous up to two years before a lump can be felt. Ductal carcinoma in situ (DCIS), an early stage of a type of breast cancer, can also be found with mammography. An early start to treatment may also stop the cancer before it spreads to the rest of the breast tissue or to other organs.

What Are the Potential Risks and Limitations of a Mammogram?

As a screening test, a mammogram cannot actually diagnose breast cancer. To diagnose breast cancer, other tests or procedures will need to be done to closely examine the suspicious tissue. A mammogram simply suggests that cancer may or may not be present. Limits of the test can lead to false results. The test can suggest that cancer is present when there is none (false positive), or it may suggest that cancer is not present when there is cancer (false negative).

Sometimes, a mammogram may suggest that there is a cancerous change in breast tissue when there really is not. Benign (noncancerous) tissue can look suspicious on a mammogram. Follow-up tests to confirm what the tissue is may include additional mammograms, ultrasound exams, breast biopsies, and other medical tests. If the original mammogram was a false positive, the additional medical tests and associated stress are unnecessary.

A review of research found that for every 2,000 women that were told to have mammograms, 200 experienced unnecessary distress because of false positive test results.

A normal mammogram does not guarantee that you are cancer free. One possibility is that the test result may be a false negative, meaning the mammogram was not able to show a cancer that was there. A clear test may also encourage a false sense of security, which may lead you to ignore symptoms that should be discussed with a doctor. You may be inclined to rely solely on mammograms instead of manual exams at doctor’s appointments or general self-health awareness.

Radiation can cause cancer and is used during a mammogram. However, the mammogram uses small doses of radiation that are considered safe. Some have voiced concerns about long-term exposure with repeated mammograms. Research has not found a link between mammogram testing and cancer development. There appears to be very little risk of harm from this radiation.

Can It Improve Your Health?

Early diagnosis is important to cancer outcomes; but do mammograms really lead to better outcomes? To help find this answer, researchers have looked at whether regular mammograms were able to decrease the rates of death from breast cancer, but the results were mixed.

Some studies suggest that mammograms can decrease the rate of cancer death, while other studies have questioned these findings. What is agreed on is that the effectiveness of the mammogram may change based on the individual and the type of cancer, for example:

  • Aggressive (fast growing) tumors—Younger women tend to have more aggressive cancerous breast tumors. By the time a mammogram finds an aggressive tumor, some cancer cells may have spread to another organ. Therefore, detection may be too late.
  • Indolent (slow growing) tumors—These are more common in older women and make up half of all breast tumors. According to the National Cancer Institute (NCI) panel, these tumors could be detected by breast exams without regular mammograms. With this type of tumor, women who perform breast self-exams and undergo breast exams by doctors would have as high a survival rate as the women who do have mammograms.
  • Inflammatory breast cancer —This can be very hard to detect by manual exam. A mammogram may be able to detect this type of cancer before visual symptoms appear.
  • High risk groups—Women with a family history of breast cancer may undergo more aggressive screening, although changes in genetic testing may change recommendations in the future.
  • Dense breast tissue—This makes it harder for mammograms to locate tumors. Young women and menopausal women on hormone therapy tend to have denser breast tissue. This can make a mammogram less effective for women in their 40’s and younger.

According to research, women who were told to have mammography screening over a 10-year period had a 15% decrease in breast cancer mortality. This means that for every 2,000 women who are told to be screened through a 10-year period, one woman will not die from breast cancer because of the screening.

Expert Advice

There are many professional, medical, and cancer groups that have their own set of mammography guidelines. The majority of guidelines agree that:

  • Beginning at age 40, women with an average risk of breast cancers should have a mammogram every 1-2 years.
  • Women who are at higher than average risk of breast cancer should seek expert medical advice about:
    • Whether they should begin screening before age 40
    • How frequently they should be screened

The US Preventive Services Task Force (USPSTF) has provided some added qualifications. The USPTF does not recommend regular mammograms for women 40-49 years of age with average risk of breast cancer. Instead, the task force suggested that each woman in this age group make an individual decision with their doctor based on her personal risks and benefits. Also, they recommend mammogram screening every two years for women 50-74 years of age, rather than every year.

Most guidelines do not have a recommended age to stop mammogram screening. The American Geriatric Society recommends mammography frequency changes to every 2-3 years after 75 years of age and the termination of screening if life expectancy is less than four years.

Putting the Pieces Together

Discuss these benefits and harms, as well as any risk factors you may have, with your doctor. This may help you make a decision on whether to have a mammography exam.

Awareness of your own health and periodic check-ins with your doctor will help identify signs of illness that need further testing, as well as ensure regular screenings. Contact your doctor if you notice a change in the look or feel of your breast.

RESOURCES:

American Cancer Society

http://www.cancer.org/

The American Congress of Obstetricians and Gynecologists

http://www.acog.org/

National Cancer Institute

http://www.cancer.gov/

CANADIAN RESOURCES:

Canadian Breast Cancer Foundation

http://www.cbcf.org/

Canadian Cancer Society

http://www.cancer.ca/

References:

Breast cancer prevention and screening. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated June 2008. Accessed July 29, 2008.

Cancer trends progress report—2007 update. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/pdq/screening/breast/HealthProfessional/page2. Accessed 11/12/2009.

Clinical guidelines: screening for breast cancer: US Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2009 Nov 17;151(10):716-726.

Ferrini R, Mannino E, Ramsdell E, Hill L. Screening mammography for breast cancer: American College of Preventive Medicine practice policy statement. AmJ Prev Med. 1996 Sep-Oct;12(5):340-341. Available at: http://www.acpm.org/breast.htm. Accessed 11/9/2009.

Get a mammogram: do it for yourself, do it for your family. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/breasthealth/. Accessed October 28, 2009.

Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database of Systematic Reviews. 2011 Jan 19;(1):CD001877.

Mammograms and other breast imaging procedures. American Cancer Society website. Available at: http://www.cancer.org/docroot/CRI/content/CRI_2_6X_Mammography_and_other_Breast_Imaging_Procedures_5.asp?sitearea. Accessed October 28, 2009.

Last reviewed December 2011 by Brian Randall, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.