Mammography Figures May Be Overestimated

Although nearly three-quarters of women over 40 say they regularly undergo mammogram breast cancer screening, a new study suggests the real number who do so is much lower -- less than two-thirds.

"There is a feeling in public health that we don't have to worry, because the majority of women are getting mammograms, but our study shows that it is still a problem. Women are overestimating their use of mammograms," says lead researcher Patricia A. Carney, the former co-director for Cancer Control Research at Dartmouth Medical School, in Hanover, N.H.

According to Carney, most studies that ask women if and how often they undergo mammography find between 65 and 82 percent saying they have had the screen within the previous two years.

But when she and her colleagues cross-checked New Hampshire census records with a state cancer registry that tracked mammogram screening over a four-year period, just 64 percent of women in the state were found to have gone for their mammogram within the recommended two-year interval.

The remaining women either had never had a mammogram, or had not had one in the previous 27 months, the team found.

Also notable was the steep drop in regular screenings among older women. Of women 80 years of age and older, 79 percent had irregular or no screenings, compared to approximately 33 percent of those women aged 40 to 79. This drop could reflect an older population more focused on other health issues, Carney says, but it could also indicate confusion about the proper guidelines for screening.

"Women 40 years and older should be screened every one to two years, and there is no upper-age cutoff," Carney says. "But I think women are very confused about guidelines."

The results of the study appear in the October 15 issue of Cancer.

Carney's team used data from the New Hampshire Mammography Network, a mammogram screening registry that receives information from more than 90 percent of the mammography facilities in the state, including hospitals, outpatient clinics and breast-imaging centers.

The population using these facilities is typically well-insured (97 percent) and well-educated (61 percent with some college or a college degree). She compared the number of mammogram screenings with the latest census to determine how many women in the state had mammograms from 1996 to 2000.

"In a state where there are very few impediments to mammography, the fact that only 64 percent are participating is a little discouraging," says Dr. Mary Newell, a radiologist at Emory University Hospital in Atlanta. "The other 36 percent fell off the screen, and we have to figure out what it is that's preventing them from getting screened."

Further, she adds, "It's interesting that there is a discrepancy between what we believe is data (on mammography screening) and what is really happening."

In Carney's study, approximately 44 percent of women were getting mammograms at 14-month intervals, and 21 percent were getting them every year-and-a-half to two years.

Another expert noted that the study is valuable in that it asked women whether they regularly went for a mammogram, unlike most other studies which often only ask women about their most recent screen.

"This study found that a relatively large group of women are not getting screened on a regular basis, and that's what is different from other studies. The regular use of mammograms is what is recommended," says Robin Yabroff, an epidemiologist with the National Institutes of Health and director of the Breast Cancer Surveillance Consortium, of which New Hampshire Mammography Network is a part.

Carney believes doctors need to communicate with their female patients about their breast cancer risk and the appropriate screening interval for them to follow. She also recommends that the public health community clarify mammography screening guidelines for women to alleviate any confusion they might have about breast cancer screening.

"We have a test that reduces the deaths from breast cancer, and people aren't using it," says Carney, who is now the associate director of population studies at the Cancer Institute, Oregon Health and Science University in Portland. "We're not doing the job we thought we were doing, or that we should be doing."

(The HealthDay Web site is at http://www.HealthDay.com.)