The Pluses and Minuses of Screening Mammograms

Early detection of breast cancer can mean the difference between life and death. The two standard tools have been the breast exam and the mammogram.

Mammograms are x-rays of the breasts. Mammograms are an effective way to detect cancer early before signs or symptoms can be seen or felt with breast exams. Screening mammography has helped to reduce breast cancer deaths among women ages 40 to 74, especially in those over the age of 50.

But mammograms also come with some minuses, especially for women under the age of 40. Here are some of the issues with mammograms.

• False-positive results — A false-positive result occurs when a radiologist sees an abnormality on a mammogram, a positive, but it turns out no cancer was actually present. A positive on a mammogram merits additional testing with diagnostic mammograms, ultrasound, and/or biopsies to determine if cancer is present. These additional tests can be costly and time consuming.
• False positives are more common for younger women, women with dense breasts, women who have had previous breast biopsies, women with a family history of breast cancer, and women who are taking estrogen for hormone therapy. Plus, the more mammograms a woman has, the greater the odds for a false-positive result.
• Overdiagnosis and overtreatment — There is some question if some cancers found on screening mammograms need to be treated. This is true of some small cancers and ductal carcinoma in situ, a noninvasive tumor. Treating these non-threatening tumors is called overdiagnosis, and it leads to overtreatment.
• False-negative results — Screening mammograms miss about 20% of breast cancers, delivering a false-negative result when breast cancer is present. This obviously gives the patient a false sense of security when she should actually be receiving treatment.

One cause of these false-negative results is high breast density. Because fibroglandular tissue appears as white areas on a mammogram (same as tumors), it can be hard to differentiate between the two. This is also true because they have similar density.

False-negative results are more common in younger women whose breasts are still more dense. Density decreases with age, particularly after 40

• Radiation exposure — Mammograms require very small doses of radiation, so the harm is low. Still, repeated mammograms do have the potential to cause cancer. Generally, the benefits of mammography outweigh the risks with radiation exposure. However, if there is any possibility that you are pregnant, extra care needs to be used because radiation can harm a growing fetus.

If you have any questions about mammograms, feel free to discuss the issue with us at Women’s Health Medical Group. Please call us at (817) 346-5336 to make an appointment.