Study questions breast biopsy accuracy
Chicago – — Here’s another reason for getting a second medical opinion: Biopsy specialists frequently misdiagnose breast tissue, potentially leading to too-aggressive treatment for some women and under-treatment for others, a study suggests.
The results indicate that pathologists are very good at determining when invasive cancer is present in breast tissue, but less adept at making the right diagnosis with less serious conditions or when biopsied tissue is normal.
The study involved 115 U.S. pathologists and 240 breast biopsy specimens. Their diagnoses were matched against those of three experts. It was an experiment and may not reflect what happens outside a research setting, but the authors say the results highlight the challenges of accurately interpreting tissue under a microscope.
The study was published in Tuesday’s Journal of the American Medical Association.
About 1.6 million breast biopsies are performed each year nationwide, typically after radiologists spot something suspicious on a mammogram. Tissue is withdrawn through a needle or from a surgically removed growth and examined under a microscope. Previous research has shown that interpreting mammograms can also be tricky and lead to under- or over-treatment.
Among the new study’s findings:
■Pathologists correctly diagnosed abnormal, precancerous cells about half the time, no better than a coin toss, said lead author Dr. Joann Elmore, a University of Washington researcher.
Treatment for this condition typically includes frequent monitoring and sometimes medication. About a third of these cases were misdiagnosed as not worrisome or normal, while 17 percent were deemed more suspicious or cancer. Since as many as 160,000 U.S. women each year are diagnosed with this condition, the results suggest many may be getting inappropriate treatment, Elmore said.
■Pathologists mistakenly found something suspicious in 13 percent of normal tissue.
“As a woman, I would probably want to get a second opinion” with a diagnosis of abnormal pre-cancer or DCIS, Elmore said.