Stereotactic breast biopsy: a surgical series

Stereotactic core needle biopsy (SCNB) is increasing in popularity and is currently being performed by both radiologists and surgeons. It has been shown to be accurate and cost effective, but the appropriate use of SCNB in the probably benign mammographic lesion has not been determined. Nor has it been determined whether a learning curve affects performance of the procedure.

The records of all patients undergoing SCNB by the author from August 1993 through May 1996 were reviewed. Two hundred forty-two patients underwent 244 procedures. Indications for biopsy, results, and complications were examined.

Probably benign mass was the most common indication for biopsy (45%), and microcalcifications were the indication for biopsy in 24%. A diagnosis of cancer was made in 11.1%. Patients with microcalcifications and probably benign masses were diagnosed with cancer in 18.4 and 1.8%, respectively. Three of eight patients undergoing open biopsy for atypical hyperplasia were diagnosed with cancer. Accuracy rate for the entire series was 97.7%. The effect of operator experience on the indication for SCNB was studied. As experience increased from the first to the last third of the study, microcalcifications as an indication increased from 23.5-37.5%. During this same time period, "probably benign" mass decreased from 53.1-32.5%.

This study demonstrates that accuracy of this surgical series is comparable to other published series. Biopsies for more difficult lesions were noted to increase as operator experience increased. It was likely that this "learning curve" was owing to improvements in technique and an increased confidence in the accuracy of the procedure. With an incidence of cancer of less than 2% in patients with a probably benign mass, interval mammography represents for many, a cost-effective alternative.