Study finds some breast biopsy analyses are often inaccurate

Items given away to promote Breast Cancer Awareness items at an event at Vandenberg Air Force Base.
Items given away to promote Breast Cancer Awareness items at an event at Vandenberg Air Force Base.
Photo by Airman First Class Ashley Reed via Wikimedia Commons

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Pathologists' analyses of certain types of breast biopsies were wrong about half the time in a study published in the Journal of the American Medical Association Tuesday.

The study involved the interpretation of breast biopsy slides by dozens of pathologists. Their findings were compared with those of an expert consensus panel.

When it came to normal biopsies and those that showed invasive cancer the pathologists were pretty much spot on, according to the study at the University of Washington Medical School.

The trouble was found in the middle range, where certain kinds of lesions known as atypia and DCIS were found. Both types are considered markers for higher risk of breast cancer.

The study found that the pathologists agreed with the expert panel only about half the time for atypia. They agreed about four out five times for DCIS, but that's still considered a low rate,  said study co-author Dr. Joann Elmore.

"We were disappointed to see that in the diagnosis of atypia and DCIS we are not doing as good of a job as we want to do," said Elmore, a professor at the University of Washington Medical School. "Now we know what the benchmark is; we can study education programs, second opinions and train a computer to help."

Each year 1.6 million women undergo breast biopsies, about a quarter of which show invasive cancer. The rest are considered somewhere between benign to pre-invasive, and that’s where the challenge lies. 

Improved mammography technology that pinpoints more abnormalities has led to an increase in the number of biopsies. Misdiagnosis of atypia or DCIS can led to under treatment or unnecessary treatment. In the case of DCIS, many women who are diagnosed with it often undergo the same treatment as those with early stage breast cancer, according to the study.

Elmore said women should listen to their doctors when they advise surveillance instead of a biopsy following a questionable mammogram. Surveillance means a woman returns for another mammogram within a shorter period of time than the once-a-year recommendation.

If a woman chooses to go ahead with a biopsy and receives a result that says she is at risk for breast cancer, Elmore said she should get a second opinion before starting treatment.

The study found that doctors who review more breast cancer tissue were more accurate in their diagnoses. 

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