Fine needle biopsy accurate in the hands of trained practitioners, UCSF study finds

Thoroughly training doctors to perform fine needle biopsies dramatically
increases diagnostic accuracy, UCSF researchers have reported.

Fine needle aspiration biopsy (FNAB), once performed extensively in doctors’
offices to identify breast and other cancers, has been falling from favor for
years as the medical community’s confidence in its accuracy has declined. It
has been replaced in many cases with more invasive procedures that carry
additional risk for patients, said the study’s lead author Britt-Marie Ljung,
MD.

The UCSF study published in the August 25 issue of Cancer Cytopathology found
that during 1992, 25 percent of breast cancers were missed at three San
Francisco hospitals because poor sampling technique resulted in inaccurate
biopsies.

“Fine needle biopsy is a great technique when performed correctly,” said Ljung,
“and it can really help patients. It’s fast, it’s inexpensive, and it’s less
likely to cause side effects like bleeding or discomfort because the needle is
so small.” Ljung is Professor of Clinical Pathology at the UCSF Comprehensive
Cancer Center.

In FNAB, physicians use a fine gauge needle to remove samples of suspicious
tissue that are evaluated microscopically. In the study group, formally trained
physicians missed two percent of cancers, whereas physicians without formal
training missed 25 percent. The formally trained physicians had completed
fellowship training in cytopathology or the equivalent, and they had performed
at least 150 FNABs under supervision.

To determine that a cancer was missed the researchers closely followed the
medical histories of 927 women at three San Francisco hospitals for a minimum
of two years. Researchers used 1043 tissue samples, patient records, and the
Northern California Cancer Registry database, which is estimated to contain 98
percent of all breast carcinomas diagnosed in the seven Bay Area counties.

According to the study, the crux of the issue was the integrity of the biopsied
tissue sample. Less-well-trained practitioners were more likely to send to the
lab samples that contained the wrong cells. Cancer was considered “missed”
either if a sample was misdiagnosed as benign, or if the sample was inadequate
to reach a diagnosis. “The difference was entirely due to errors in sampling
the lesion rather than in interpreting the specimen,” the study authors said.

Patient charts indicated the location of a tumor within a patient’s breast,
allowing researchers to correlate the tumor to the earlier biopsy. “The only
factor that made a difference in the rate of accurate diagnosis was the
training of the practitioner,” said Ljung.

Although the study only examined breast biopsies, the findings have broader
implications, since FNAB can be used for any organ, she said. Many physicians
who have observed low rates of accuracy in FNAB have turned to other methods.
But when FNAB is replaced by surgical or core biopsy, costs rise, patients can
endure delays, and the risk of complications increases, according to Ljung.

“One solution to the problem of substandard FNAB results is to train a number
of physicians well enough so that they can achieve a reliable diagnosis. We
suggest that FNAB be concentrated in well-trained hands to provide the benefit
of high-quality, rapid, minimally invasive diagnosis to the maximal number of
patients,” said the authors.

The hospitals included in the study were: California Pacific Medical Center,
UCSF Mount Zion, and UCSF Moffitt Long. The research was supported by a grant
from the Department of Defense to the Carol Franc Buck Breast Care Center. The
Breast Care Center is part of the UCSF Comprehensive Cancer Center, an
interdisciplinary initiative that combines basic cancer science, clinical
research, epidemiology/cancer control, and patient care programs throughout the
campus of the University of California, San Francisco.