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Large-Core Needle Biopsy Reduces Need for Surgical Biopsies

Large-Core Needle Biopsy Reduces Need for Surgical Biopsies

SEATTLE—A fully implemented large-core needle biopsy program can
dramatically improve the positive predictive value of surgical biopsy of breast
lesions, based on the experience of the Brigham and Women’s Hospital, Boston.
Jessica Leung, MD, instructor in radiology, Harvard Medical School, presented
the study at the 101st Annual Meeting of the American Roentgen Ray Society.

"By obviating the need for surgery of benign lesions, core biopsy
should increase the cancer yield at surgical biopsy after wire
localization," Dr. Leung said.

Other studies have addressed this topic, but the study presented by Dr.
Leung had some key differences. "Our design is unique in that our study
period is 7 years after the implementation of core biopsy—in other words,
sufficient time has elapsed for our program to be fully implemented," she
said. Furthermore, the study had large enough numbers to achieve high
statistical significance.

The researchers also investigated the manner and degree in which core biopsy
affects surgical biopsy yield. They compared the cancer yield of surgical
biopsy during a 2-year study period after full implementation of the large-core
needle biopsy program (July 1, 1998, through June 30, 2000) and a 2-year
control period before core biopsy was widely used (January 1, 1987, through
December 31, 1988). Surgical biopsy was performed for 1,163 lesions in the
study group and 1,261 lesions in the control group.

The overall positive predictive value of surgical biopsy was 0.19 before
core biopsy was implemented and 0.42 after core biopsy was implemented. When
the lesions were stratified into masses and calcifications, the positive
predictive value for masses increased from 0.21 to 0.47, and for
calcifications, from 0.17 to 0.37. The results were statistically significant (P < .0001) for all three comparisons.

The histologic subtypes of the cancers diagnosed by surgical biopsy differed
little for the two periods. In both the study and control groups, invasive
ductal carcinoma was the most common diagnosis (53.8% and 59.5%, respectively)
followed by ductal carcinoma in situ (36.2% and 35.8%, respectively).

"The total number of surgical biopsies remained constant despite the
implementation of core biopsy. This reflects an increase in our practice over
the years in the overall volume of imaging-guided breast biopsy," Dr.
Leung said. The ratio of in situ vs invasive carcinomas remained constant, she
added, "supporting the contention that our historical cohort and our study
population are comparable."

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