Newswise — While doctors almost always agree on a pathological diagnosis of invasive breast cancer, there is room for improvement when diagnosing atypia (or atypical ductal hyperplasia-ADH) and DCIS (ductal carcinoma in-situ), Anna Tosteson, ScD and Tracy Onega, PhD from Dartmouth-Hitchcock's Norris Cotton Cancer Center have found. The Dartmouth investigators, and national collaborators, published the study, "Diagnostic Concordance Among Pathologists Interpreting Breast Biopsy Specimens," today in JAMA.

"About 1.6 million breast biopsies are done every year in the U.S., yet in nearly half of the cases labeled atypia, our study indicates that there simply isn't 'concordance,' meaning there is not agreement with a standard reference diagnosis," explained Tosteson. In the study, a panel of three expert pathologists determined the reference diagnosis for each of 240 cases that included 23 cases of invasive breast cancer, 73 DCIS, 72 with atypical hyperplasia (atypia), and 72 benign cases without atypia.

The accuracy of breast biopsy diagnoses has not been well studied, but it is a critical element in treating women with breast disease appropriately. This work takes a new approach to informing what is known about the over- and under-interpretation for breast cancer and benign breast disease, and identifies the greatest clinical challenge for accurate interpretation. The study involved 115 participating pathologists from 8 states, providing a total of 6,900 breast pathology interpretations. The overall concordance rate was 75.3%, with a rate of 96% for biopsies with invasive carcinoma. The concordance rate for atypia was just 48%, and it was 84% for DCIS.

"Our findings show that, particularly for women with dense breasts, the lack of consensus in diagnoses of atypia or DCIS is considerable," explained Onega. "The take-home message for women is that it's not overly cautious to seek a second opinion with one of these diagnoses. In fact, it's likely to be a good idea."

The next steps for the Dartmouth investigators include assessing the various ways breast biopsies can be evaluated and their relative impact on patient management. Dartmouth's Office of Cancer Comparative Effectiveness Research at Norris Cotton Cancer Center and the New Hampshire Mammography Network are actively supporting this ongoing research.

Tosteson is the James J. Carroll Professor at Dartmouth's Geisel School of Medicine, co-Director of the Cancer Control Research Program at Dartmouth's Norris Cotton Cancer Center, and a Professor at The Dartmouth Institute for Health Policy and Clinical Practice. Onega is Associate Professor of Biomedical Data Science, Epidemiology, and The Dartmouth Institute for Health Policy and Clinical Practice at Dartmouth's Geisel School of Medicine.

"Diagnostic Concordance Among Pathologists Interpreting Breast Biopsy Specimens," was funded by the National Cancer Institute grants RO1 CA140560 and K05-CA104669, and by the National Cancer Institute-funded Breast Cancer Surveillance Consortium UO1CA86082, UO1CA70013, UO1CA69976, HHSN261201100031C.

About Dartmouth-Hitchcock Norris Cotton Cancer Center

Norris Cotton Cancer Center combines advanced cancer research at Dartmouth and the Geisel School of Medicine with patient-centered cancer care provided at Dartmouth-Hitchcock Medical Center in Lebanon, NH, at Dartmouth-Hitchcock regional locations in Manchester, Nashua, and Keene, NH, and St. Johnsbury, VT, and at 12 partner hospitals throughout New Hampshire and Vermont. It is one of 41 centers nationwide to earn the National Cancer Institute's "Comprehensive Cancer Center" designation. Learn more about Norris Cotton Cancer Center research, programs, and clinical trials online at

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RO1 CA140560; K05-CA104669; UO1CA86082; UO1CA70013; UO1CA69976; HHSN261201100031C; JAMA