Mammogram Benefits, Drawbacks, and Myths

Weigh Your Benefits and Risks, Dispel Myths About Mammography

Woman having Mammogram exam.
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Mammograms – the annual squeeze that many women dread – is an effective screening tool for breast cancer as well as benign breast conditions. It is not a perfect tool and is sometimes misunderstood by women who have had less-than-pleasant experiences with it. Here you can weigh the benefits and drawbacks, and learn some myths about mammography.

Benefits of Mammograms

Early Detection
Before you can feel a lump, a mammogram can detect it.

When a cancer is that small, it may be well-contained (as in not spreading), and may be successfully treated. Standard breast cancer treatments are most effective on smaller tumors. Women over 50 reap the most benefit from mammograms, because their breasts are less dense, which are more effectively imaged by mammography. Women who are 40 to 49 years old still benefit from mammograms but are more likely to have more benign findings. In certain women and circumstances, routine mammography is supplemented with other imaging technologies such as ultrasound, MRI, and molecular breast imaging (MBI).

In Situ, Invasive Breast Cancer and Age Factors
Mammograms are good at catching invasive breast cancer, whether you are under or over 50. Invasive breast cancer means it has broken out of its original site and invaded nearby tissues. In situ breast cancers such as ductal carcinoma in situ and lobular carcinoma in situ, are contained in one place, such a milk duct or lobe.

For women under 50 with dense breasts, mammograms may miss a small percentage of in situ breast cancers.

Drawbacks of Mammograms

False Positives: Abnormal Results From Your Mammogram
If you get abnormal results from your mammogram, stay calm. Only one out of every 10 women who have abnormal mammogram results will have breast cancer.

The emotional cost of a false positive can't be put into financial terms – but getting such news can be a real blow. There are several reasons that you may get a false positive: Mammograms are less accurate on women under 50 years old, results can vary among radiologists (more experienced radiologists have higher accuracy), and going to a different clinic every year can throw off your results. Digital mammography may prove to be faster, safer, and more accurate than film mammography.

False Negatives: Mammograms And Dense Breasts
Mammograms work most accurately on breasts with a good amount of fatty tissue – and not as well on breasts that are dense (less fatty tissue). Lumps and bumps can hide from mammograms in dense breast tissue or may appear to be suspicious when they are really benign. A two-year study of 2,809 women found that mammograms were highly accurate in detecting cancer in dense breasts, but when combined with ultrasounds, more cancers were found, but also more false positives resulted. False positives (inaccurately diagnosed masses that are not cancerous) were confirmed by breast biopsy.

Myths About Mammograms

Mammograms Cause Breast Cancer: False
Your breast receives about two "rads" or less during a mammogram, according to the U.S. Food and Drug Administration (FDA), the agency that regulates and certifies mammography machines as well as doctors and technicians.

Two rads (radiation absorbed dose) is about the same as you absorb when you have dental x-rays, and is less than the radiation used for a standard chest x-ray. The Mammography Quality Standards Act (MQSA) has set the required level of radiation to the lowest possible dose that will obtain the best possible image. Twenty years ago (1988 and earlier) a mammogram used 50 times the amount of radiation than is used today. Modern mammography equipment uses a very low dose of radiation, which should cause no long-term side effects.

Mammograms Are Always Painful: Yes, But -
A breast is a three-dimensional part of your body and a sensitive one at that.

A screening mammogram takes a two-dimensional x-ray of your breast. In order for the x-rays to effectively make the image, your breast tissue must be compressed and must be quite still. You can do three things to lessen the pain of a mammogram: use lidocaine gel in advance of your appointment to numb the breast, schedule your appointment about one week after your period starts, cut down on caffeine for two weeks prior to your mammogram, and request a comfort pad (if your clinic has these) to cushion your breast during the imaging process. Patients who participated in a study of the BioLucent MammoPad said that it reduced their breast pain by nearly half of what it would be without a pad or pain medication.


U.S. Food and Drug Administration. Mammography. Frequently Asked Questions About MQSA. Updated August 29, 2008.

JAMA. 2008;299(18):2151-2163. Combined Screening With Ultrasound and Mammography vs Mammography Alone in Women at Elevated Risk of Breast Cancer. Wendie A. Berg, MD, PhD, et al.

Ann Intern Med August 2003;139:274-85. Kerlikowske K, et al. Evaluation of abnormal mammography results and palpable breast abnormalities.

False positive mammograms and detection controlled estimation - Methods - a research project examines the incidence of false positive mammograms using the detection-controlled estimation technique. Health Services Research, August, 2003 by Andrew N. Kleit, James F. Ruiz.