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 The researchers asked three different pathologists to give a second
opinion on women's biopsy slides. When the slides showed either
invasive breast cancer, or harmless or benign cells, the doctors
agreed with the original diagnosis at least 97 percent of the time.
But when the initial diagnosis was “atypia” – healthy cells that
grow faster than normal – the pathologists thought doctors had
originally overestimated the danger in more than half of cases. And
they thought doctors had overestimated the danger for almost one in
five women who were originally diagnosed with a common noninvasive
malignancy of the breast known as ductal carcinoma in situ (DCIS).
"It's easier for physicians to diagnose diseases at the extremes of
the spectrum – we are good at diagnosing normal breast tissue and
the very abnormal cells of invasive breast cancer," said lead study
author Dr. Joann Elmore of the University of Washington School of
Medicine and Harborview Medical Center in Seattle.
"Between these extremes, agreement of pathologists deteriorates,"
Elmore added by email.
Atypia and DCIS are gray areas on a spectrum of cancer severity
between benign, or generally harmless, cells and fast-growing
invasive tumors, said Dr. Richard Bleicher, breast clinical program
leader at Fox Chase Cancer Center in Philadelphia.
"It's sort of akin to trying to differentiate blue from teal from
green – there is a bit of subjectivity," said Bleicher, who wasn't
involved in the study.
For the study, three different pathologists working independently
reviewed one biopsy slide apiece from 240 women aged 50 to 59.
Overall, they agreed with the original biopsy diagnosis about 92
percent of the time, Elmore and colleagues report in the Annals of
Internal Medicine.
They thought about five percent of the original diagnoses had
overestimated the danger, and roughly 3 percent had underestimated
the cancer risk.
In the real world, pathologists might have consulted with colleagues
or requested additional tissue samples if the diagnosis wasn’t clear
from one slide, potentially increasing the accuracy of diagnoses and
limiting the disagreement among doctors, the authors note.
Still, the findings highlight the challenges doctors and patients
face in deciding the best course of action when results don’t fall
clearly into an extremely low-risk or high-risk category, Elmore
said.
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Women with an abnormal mammogram may rush to get a biopsy, hoping
for an immediate resolution and a clear diagnosis, Elmore noted. But
when the biopsy results fall in a gray area, their path forward
isn't always as clear cut as they would like.
"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; they have time to obtain a second opinion to verify the
diagnosis," Elmore said.
At the same time, women may find that even when doctors agree on the
diagnosis, they may not agree on treatment, Dr. Alexander Borowsky,
a researcher at the University of California, Davis, wrote in an
editorial.
When doctors overestimate the cancer risk, some women may suffer
side effects from treatment that probably didn't lower their odds of
dying from breast cancer, Bleicher noted. For example, some women
with atypia or DCIS may be given tamoxifen, a drug to treat or
prevent cancer that can also trigger early menopause.
In the opposite circumstance, when doctors underestimate severity,
women may miss an opportunity to get radiation or chemotherapy at an
earlier stage of cancer when it may be more effective.
"We have a critical need to validate the tools that diagnose
disease, especially these categories in the gray area between normal
and cancer," Elmore said. "Our results underscore persistent
difficulties with medical diagnoses based on clinical judgment."
SOURCE: http://bit.ly/1i46lF7 Annals of Internal Medicine, online
March 21, 2016.
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