A University of Washington study found that pathologists interpreting slides of breast biopsies agreed almost completely on cases of invasive breast cancer, but had greater differences in cases of more subtle cell abnormalities.
The study, published in the Journal of the American Medical Association, was led by Dr. Joann Elmore, professor of medicine in the School of Medicine and adjunct professor of epidemiology in the School of Public Health. More than 1.6 million breast biopsies are conducted each year in the U.S. “Our goal was to evaluate the accuracy of doctors’ interpretations,” said Dr. Elmore, who is also an affiliate investigator at the Fred Hutchinson Cancer Research Center.
The study included 115 pathologists from eight U.S. states who reviewed biopsy slides from 240 total cases. The slides were examined between November 2011 and May 2014, and the pathologists’ results were compared with findings from a panel of three international experts who reviewed the same slides.
Pathologists agreed with the expert panel about 96 percent of the time on cases of invasive breast cancer, according to the study. The pathologists agreed with the experts in about four out of five cases in diagnosing ductal carcinoma in situ, or DCIS. They concurred with the panel in less than half of cases of interpreting atypical cells, or atypia.
“We were surprised by the amount of disagreement among these doctors,” Dr. Elmore told JAMA. Researchers suggest clinicians and patients may want to obtain a second opinion for breast atypia before undergoing additional surveillance, treatment or surgery.