A study has found that as many as one of every four breast tissue biopsies tested for cancer may have been incorrectly diagnosed by pathologists.
According to a study in the journal JAMA, the journal of the American Medical Association, when it comes to less obvious biopsy cases, pathologists – the doctors giving the diagnosis – only agree with outside experts about 75% of the time.
The study prepared 240 breast cancer biopsy slides to be diagnosed by 115 pathologists. Their answers were then compared to those determined to be the correct diagnosis by a panel of three highly regarded experts.
The doctors correctly identified invasive breast cancer 96% of the time. With normal tissue, their diagnosis was right 87% of the time.
However, when it came to more complicated cases like DCIS and atypia where the cells are abnormal, of which both have the possibility to become invasive cancer, the doctors misdiagnosed 16% and a troubling 52% of the time respectively.
With atypia, 17% of the readings were false positives, meaning a patient might undergo treatment she doesn’t need, and 32% were false negatives, where women didn’t know that they had an increased risk of cancer since the pathologist gave a misdiagnosis in the first place.
According to pathology researcher Dr. David Rimm, invasive cancer is easy to spot. “Here are criteria I can write down: This cluster of cells has enlarged and irregularly shaped nuclei and architecturally irregularly shaped clusters and high nuclear to cytoplasmic ratio.”
But when it came to abnormal cells like DCIS and atypia, it gets more complicated. “And what if it has some suggestion of enlargement or some suggestion of arch irregularity?" Rimm asks. "Then we get into that gray area. That's what happens. That's the real world.”
Dr. Jean Simpson, president of the Breast Pathology Consultants in the U.S., gives advice for women who want more reassurance of their diagnosis. “I will tell patients that a second opinion is a fairly inexpensive process. And what value can you put on peace of mind?” she told npr.org.
Sources: March 19, 2015. "Diagnosed With Breast Cancer? Get a Second Opinion". time.com March 18, 2015. "How Much Can Women Trust That Breast Cancer Biopsy?". npr.org March 17, 2015. "Study Questions Accuracy of Breast Cancer Biopsies". webmd.com