Mammogram accuracy varies by radiologist: study
By Julie Steenhuysen
CHICAGO (Reuters) - Women with lumps in their breasts rely on their radiologists to accurately read their mammograms, but the accuracy of those readings varies widely, U.S. researchers on Tuesday.
Earlier studies found variation in the quality of screening mammograms. But the new research found inconsistencies even when a lump was present, leaving some women open to false positive results or even missed diagnoses, said Diana Miglioretti, a researcher at the Group Health Center for Health Studies in Seattle, whose study was published in the Journal of the National Cancer Institute.
Miglioretti and her team evaluated 123 radiologists who looked at 36,000 diagnostic mammograms from 1996 through 2003 at 72 U.S. facilities, including six from Group Health, a nonprofit health maintenance organization in Washington.
They found that sensitivity -- the ability to accurately detect cancer -- ranged from 27 percent to 100 percent. False positives ranged from 0 to 16 percent.
"On average, 21 percent of breast cancers were missed and 4.3 percent of women underwent a biopsy even though they didn't have breast cancer," Miglioretti said in a telephone interview.
This variability was evident even after accounting for differences in physical characteristics.
Miglioretti said the results surprised her.
"I was expecting diagnostic mammograms to be less variable than screening mammograms," Miglioretti said. Diagnostic mammograms are those performed on women whose initial, screening mammograms raise concern about the possibility of cancer.
The study included data from rural hospitals, where radiologists may not handle a high volume of diagnostic mammograms.
Miglioretti said women might want to consider scheduling diagnostic exams at centers with breast imaging experts. "It might be worth driving the extra hour to find one. It is not always possible," she said.
The study was funded by grants from the National Cancer Institute, Agency for Healthcare Research and Quality and Breast Cancer Surveillance Consortium.
There will be an estimated 178,000 new cases of breast cancer in the United States this year, with 40,000 deaths.
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Mammogram accuracy varies by radiologist: study
According to the study reviewed here, radiologists' ability to accurately read diagnostic mammograms varies widely -- from 27% to 100%. Radiologists who work at academic medical centers are likely to be more adept at interpreting diagnostic mammogram results. This result is not mentioned in the article presented here, but it is an important finding.
The study focused on interpreting diagnostic mammograms -- mammograms done on women who have a suspicion of breast cancer (such as an abnormal screening mammogram or a breast lump).
Radiologists working at academic medical centers accurately read diagnostic mammograms 88% of the time, compared to non-academic radiologists who accurately read diagnostic mammograms 76% of the time.
Mammograms are probably the most important tool doctors have to help them diagnose, evaluate, and follow women who've had breast cancer. But mammograms aren't perfect. Sometimes cancer is missed, a situation called a "false negative." And sometimes mammogram results are interpreted as cancer even though no cancer is present. This is called a "false positive."
False negatives can cause a critical delay in diagnosis and treatment. While not life-threatening, false positives can mean more tests and follow-up doctor visits, as well as tremendous stress and anxiety.
Not everyone has an academic medical center nearby. But that doesn't mean you can't get the excellent care you deserve. To make sure you get the most accurate mammogram reading possible, consider taking the following steps:- Ask healthcare professionals you trust which imaging center they recommend.
- Insist that your new mammogram be compared with your older mammograms when it's being read. This has been shown to improve the accuracy of mammogram readings.
- Ask if a second person routinely reviews any suspicious mammograms before a final interpretation is made. A second reading also has been shown to improve mammogram accuracy.
For more information on mammograms and other tests to detect breast cancer, visit the breastcancer.org Screening and Testing section.