March 17, 2015


UW study: Breast biopsy results may not be accurate (JoNel Aleccia, 3/17/15, The Seattle Times)

The new study provides the first updated analysis of pathologist disagreement since the 1990s.

Elmore and her colleagues, including scientists at Seattle's Fred Hutchinson Cancer Research Center, compared the findings of 115 pathologists from eight states -- Alaska, Maine, Minnesota, New Hampshire, New Mexico, Oregon, Vermont and Washington -- with the results of an expert panel between November 2011 and May 2014.

The participating pathologists were randomly assigned to review one of four test sets of 60 breast biopsy slides, offering a diagnosis for each case. The slides were weighted to include more than expected cases of atypia and DCIS, cases from women aged 40 to 49 and women with dense breast tissue, because age and density are important risk factors for both benign breast disease and cancer, the study said.

Compared with the experts, the pathologists under-interpreted, or missed, about 4 percent of invasive carcinoma, about 13 percent of DCIS cases and about 35 percent of atypia cases, researchers found. They over-identified atypia in about 17 percent of cases, DCIS in 3 percent of cases and benign breast disease without atypia in 13 percent of cases.

The disagreement was higher among pathologists who interpret fewer cases each week and those who worked in smaller practices or nonacademic settings.

Such inaccurate findings could have direct impact on women's care, said Dr. H. Gilbert Welch, a professor of medicine at Dartmouth University who was not involved in the study. Of the DCIS cases identified by the pathologists, about 18 percent were actually not DCIS, which is typically treated in the same way as invasive carcinoma.

That means that, based on the diagnoses, many women would be advised to undergo lumpectomy, mastectomy and other treatments that weren't actually warranted, said Welch, the author of the new book "Less Medicine, More Health: 7 Assumptions that Drive Too Much Medical Care."

"Pathological disagreement is still a problem in the modern century," Welch said.

Posted by at March 17, 2015 3:32 PM

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