By Evan Evans, M.D.
After years of advising that women should have yearly screening mammograms beginning at age 40, the U.S. Preventive Services Task Force (USPSTF) recently reversed their previous recommendation. The decision was based on a low benefit for women aged 40 – 49 and a high risk of a false positive mammograms. Instead, they suggest that screening should occur every other year for women from 50 to 74.
This announcement raised more questions than were answered. As a radiologist who is fellowship trained in breast imaging, I delved beyond the headlines and studied their announcement to find the answers.
First, no significant new data caused the task force to change their recommendation. They studied many trials which analyzed the reduction of breast cancer deaths due to screening mammograms since 1960. The USPSTF did not weigh the quality of the information provided by a given trial, only its published results.
To assign equal importance to 1960s studies versus recent trials ignores the significant improvement in image quality and the training and documentation required to interpret mammograms. Recent studies indicate that digital mammograms considerably increase breast cancer detection for women with dense breast tissue compared to traditional film mammography. Half of women under the age of 50 have dense breast tissue.
The widespread use of digital mammography, as well as new advances awaiting FDA approval, will undoubtedly further decrease the mortality from breast cancer among women who participate in yearly screening.
As radiologists, we are keenly aware of the high costs to a woman for a false positive mammogram, both in terms of anxiety as well as the actual monetary costs of the further study required. However, published studies indicate that the majority of American women prefer an earlier diagnosis of breast cancer even if this strategy results in a higher number of false positives.
What does a false positive mean? On average, for every 1000 women screened, between 85 and 100 are recalled for additional views and usually breast ultrasound. For 45 to 65 of these patients, the further evaluation eliminates any concern, and they may resume yearly screening. About 15 to 20 women from the recalled group will be asked to return in six months for a second look, the “probably benign” category. On average, the remaining 15 will receive a biopsy recommendation. Of these, 3 to 5 will be diagnosed with breast cancer, with the remainder of the biopsies representing benign tissue.
In conclusion, the USPSTF indicated that women from 40 – 49 should decide for themselves whether they would benefit from an annual mammogram. But advances in technology and the recommendations of other experts in the field tip the scales in favor of an annual mammogram.
Dr. Otis Brawley, chief medical officer of the American Cancer Society, reaffirmed his and the ACS’s commitment to recommend annual screening mammography beginning at age 40. He states, “This is one screening test that I recommend unequivocally and would recommend to any woman 40 and over, be she a patient, a stranger, or a family member.”
Each year, of the approximately 186,000 new cases of breast cancer in the U.S., 29,000 of these cases will occur in women between the ages of 40 and 49. Although not a perfect test, mammography is the only breast cancer detection method which has proven to reduce a woman’s risk of dying from breast cancer.
Board-certified radiologist Evan Evans, M.D., has completed a fellowship in breast imaging at Parkland Health and Hospital System in Dallas. He currently serves as medical director of radiology at Huguley Memorial Medical Center.