CHICAGO—New studies are beginning to demonstrate the real-world implications of the U.S. Preventative Services Task Force (USPSTF) screening mammography guidelines. A trio of papers presented Monday at the annual meeting of the American Roentgen Ray Society (ARRS) suggested that primary care physicians are referring fewer patients age 40 to 49 for screening mammography and fewer women in that age cohort are seeking screening exams. A retrospective study indicated that unscreened women are diagnosed at later stages.

Updated in November 2009, USPSTF guidelines recommended against screening mammography for women age 40 to 49 and advised biennial screening for women age 50 to 74.

Changing physician ordering patterns

When researchers at the University of Colorado in Denver surveyed 303 primary care physicians about screening practices before and after the releases of the guidelines, they found statistically significant decreases in ordering patterns for women age 40 to 49, reported Jayme Takahashi, MD, a fourth-year radiology resident at University of Colorado in Denver.

Takahashi noted that 16.5 percent of physicians responded to the survey.

Prior to the 2009 guidelines, for patients aged 40 to 49, 56 percent of physicians recommended screening mammography, 33 percent recommended biannual screening and 11 percent advised against screening.

After the guidelines were revised, 20 percent recommended annual screening, 18 percent recommended biannual screening and 8 percent advised against screening. Fifty-four percent of patients reported discussing the risks and benefits of screening mammography with women age 40 to 49 after the release of the guidelines.

Among women age 50 to 74, prior to the USPSTF guidelines, 94 percent of physicians advised annual screening mammograms and 6 percent recommended biannual mammograms.

After the guidelines were released, the percent of physicians recommending annual screening mammography in this age group fell to 74 percent, with 16 percent recommending biannual exams. In addition, the percent advising against screening increased from zero to 2 percent, and 8 percent of physicians reported discussing the risks and benefits of screening mammography with their patients.

Among women older than 74, prior to the release of the guidelines, 58 percent of physicians recommended annual screening mammograms, 7 percent recommended biannual exams and 35 percent advised against screening mammography.

After the guidelines were updated, 32 percent of physicians recommended annual mammograms for women older than 74, 10 percent recommended biannual exams and 8 percent advised against screening, with 50 percent discussing risk and benefits of screening mammography with patients.

Takahashi calculated that 62 percent of physicians follow USPSTF guidelines for women age 40 to 49, 16 percent follow the guidelines for women age 50 to 74 and 8 percent follow the guidelines for women older than 74.

The USPSTF guidelines have caused a significant difference in screening mammography ordering patterns among all three age groups, with a more pronounced impact among women age 40 to 49, concluded Takahashi. She noted that while there are more discussions occurring between physicians and patients, fewer annual and routine screening mammograms are occurring, with the predicted result being fewer false positives and a possible tradeoff in the detection rate.

The patient impact

Lara A. Hardesty, MD, of University of Colorado, devised a related study and examined the effect of guidelines on women seeking mammograms.

Researchers mined institutional mammography databases to calculate the number of women presenting for screening mammograms in the nine months preceding the release of the guidelines (February 2009 to November 2009) and the nine months following the release (November 2009 to August 2010) among women age 40 to 49 and women 50 and older.

Before the guidelines were released, 1,327 women presented for screening mammography. In the nine months following the release, the number dropped to 1,122, a statistically significant decrease of 15.4 percent.

Among women older than 50, 4,479 women presented for screening mammography in the nine months prior to the release of the guidelines, which increased to 4,498 after the guidelines.

“It’s unknown why the guidelines affected the participation of women age 40 to 49, but not those over the age of 50,” Hardesty admitted. She hypothesized the drop might relate to different provider recommendations. Another possible explanation, surmised Hardesty, might be that women made the decision not to pursue screening mammograms based on media coverage of the new guidelines.

The impact on diagnosis

Mallory Kremer, MD, from the school of medicine at Case Western Reserve University in Cleveland, devised a study to analyze the effect of the guidelines on breast cancer diagnosis among women age 40 to 49.

The study consisted of an electronic chart review of all women age 40 to 49 undergoing image-guided core needle biopsies at Case Western Medical Center between 2008 and 2009. Kremer and colleagues divided women into screened and unscreened cohorts, defining unscreened women as those presenting with a symptomatic complaint, who had not participated in screening mammography 12 months prior to presentation.

The 511 biopsies indicated 108 primary breast cancers, with 71 found in screened patients and 37 occurring in unscreened patients.

There was a greater proportion of DCIS in the screened cohort, said Kremer, with approximately one-third of cancers in the screened group classified as DCIS vs. less than five percent in the unscreened group.

Among women diagnosed with invasive cancers, nearly half of the screened patients presented at stage 1. In contrast, one-quarter of unscreened women were diagnosed with stage 1 cancer. In addition, screened women had a higher probability of being detected with a smaller tumor and node negative disease.

Kremer noted that in addition to improving outcomes earlier detection also allows women to avoid more intense treatment.

“With recent changes in screening guidelines, alterations inreferring physician practices and overall poor patient adherenceto screening recommendations, survival rates in this populationwill decline," she concluded. "We continue to recommend annual mammography in women between the ages of 40 and 49 years.”