skip navigation , health centers and clinics , search , accessibility statement , Página en español ,
Contra Costa Health Services
contact us

Home > Health Topics > Healthy Outlook > Early Breast Exams May Produce False Positive

Early Breast Exams May Produce False Positive

Published by Contra Costa Times
Posted on Wednesday, February 1, 2012
By Dr. Jane McCormick

There seems to always be discussion about when women should begin receiving mammograms. The discussion gets even more complex when you begin talking about dense breast tissue.

Dense breasts are common in women under the age of 50, because younger women have a higher proportion of dense connective tissue compared to fatty tissue. The connective tissue is what allows the breast to function as a producer of milk. As women age, fatty breast tissue increases and connective tissue decreases.

Mammograms are easier to interpret when the patient’s breasts have more fat. That is because an abnormal area will look white on a background that is mostly black. When a woman has dense breasts, the background is also white, making it harder to tell what is normal and what is abnormal. This is one of the reasons there is debate about what age women should begin screening mammograms.

One of the complicating factors of having higher than usual breast density is a slightly higher risk of developing breast cancer. There are currently studies trying to evaluate this. If you have extremely dense breasts, you might reasonably worry that a mammogram may miss an early breast cancer. We don’t know if women with dense breasts should have a different exam, but we do know that digital mammography is preferred because it is more sensitive than film mammography.

The benefit of ultrasound or MRI screening, in addition to mammography, is uncertain. At the moment, there is concern that MRIs find too many abnormalities that turn out to be nothing. This causes a great deal of anxiety, and unnecessary biopsies. Because of this, women who have dense breasts with no other risk factors for breast cancer should have routine mammograms, ideally digital.

Annual MRIs are only recommended for women who have both dense breasts and are at a higher risk for breast cancer based on family history. Alternatively, ultrasound plus mammography may increase the cancer detection rate, compared to mammography alone, in women with dense breasts and increased cancer risk.

All experts agree that women aged 50 and older should have screening for breast cancer, including a mammogram and a breast exam. There is controversy about the use of mammograms among women in their 40s because breast cancer is less common at that age and false positives are more common. Some experts recommend women start screening as early as age 40.

Discuss your personal risks and benefits to beginning screening with your health provider at age 40. You should also be familiar with your breast exam and learn how to perform a self-exam.

Patients who should be screened beginning at age 40 include women who have close relatives with breast cancer at an early age, or who have a history of an abnormal breast biopsy.

It is important for your health provider to know your family history and about any previous breast abnormalities you may have had. If possible, bring copies of past biopsy reports to your visit. If you have a history of dense breasts, ask your health provider about the availability of digital mammography. If you and your health provider determine that you have increased risk factors for breast cancer, consider screening MRI or adding ultrasound screening to your annual mammogram.

Dr. McCormick is a family practitioner who works in the Oncology Clinic at the Contra Costa Regional Medical Center.


Contra Costa County home page