Although doctors strongly agree on the diagnosis of invasive breast cancer, most doctors often disagree when diagnosing breast biopsy results for ductal carcinoma in situ (DCIS) and atypia, a new study revealed.
Led by Dr. Joann Elmore of the University Of Washington School Of Medicine, the team of experts began examining diagnostic agreement among pathologists while interpreting breast biopsies in 2009.
In the B-Path (Breast Pathology) study, researchers asked three different pathologists to give a second opinion on different biopsy slides - exactly one biopsy slide apiece from 240 women who were 50 to 59 years old.
When the slides displayed invasive breast cancer or benign cells, they agreed with the initial diagnosis 97 percent of the time.
However, when the original diagnosis was atypia, which are atypical cells that grow faster than normal, pathologists thought the diagnosis in more than half of the cases may have been originally overestimated. Pathologists also thought doctors overestimated the danger for women who were initially diagnosed with DCIS.
Elmore said that pathologists' overall interpretation of B-Path results across the United States would be confirmed by an expert panel 92 out of 100 biopsies. Most of the original diagnosis is over-interpreted than under-interpreted, she said.
What's more, the study found that among 100 breast biopsies that received an initial diagnosis of atypia, less than half would maintain the diagnosis after review by a panel of three experienced pathologists. More than half would be downgraded from atypia to a diagnosis of benign without atypia, Elmore said.
Atypia and DCIS are gray areas on a spectrum of cancer severity. It generally swings from generally harmless or benign to rapid-growing invasive tumors, an expert said.
Dr. Richard Bleicher, who wasn't involved in the study, said the difference between atypia and DCIS are similar to differentiating blue from teal from green.
"There is a bit of subjectivity," said Bleicher, who is a breast clinical program leader at Fox Chase Cancer Center.
Meanwhile, Elmore said it is easier for doctors to diagnose at the extremes of the spectrum. But between these extremes, the agreement starts to deviate.
Elmore said that when women are confronted with a diagnosis of DCIS or atypia, they may want to consider getting a second opinion before pursuing treatment.
"I encourage women who receive an initial diagnosis of either atypia or DCIS to realize that they do not need to act immediately on the results," said Elmore. "They have time to obtain a second opinion to verify the diagnosis."
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The danger here is that women whose doctors disagree on diagnosis may also disagree on treatment, said Dr. Alexander Borowsky who wrote an accompanying editorial for the study.
In fact, Bleicher also said that when doctors over-interpret the cancer risk, some women may suffer side effects from treatment that possibly did not reduce their odds of dying from breast cancer. For instance, women with DCIS or atypia may receive the drug tamoxifen to treat cancer, but it can also trigger early menopause.
On the contrary, when doctors under-interpret diagnosis, women may miss a chance to get chemotherapy or radiation at an earlier stage of their illness when the treatment can be more effective, Bleicher said.
Meanwhile, Elmore said further research must be done to find out whether diagnostic uncertainty could be objectively measured and integrated into breast disease management.
"We have a critical need to validate the tools that diagnose disease, especially these categories in the gray area between normal and cancer," added Elmore.
"Getting the diagnosis right is an important first step," she said.
The findings of the study are featured in the journal Annals of Internal Medicine.
Photo: Gerry Lauzon | Flickr