Learning Curve for Add-on Stereotactic Core Needle Breast Biopsy

Purpose: To evaluate the learning curve for an add-on 14 G stereotactic core needle biopsy (SCNB). Material and Methods: A total of 231 non-palpable breast lesions that had undergone add-on SCNB were evaluated in this prospective study. Five radiologists performed their first three biopsies under supervision. Subsequent, independently performed, biopsies were also evaluated. The samples were collected in three different containers: the first sample in container A, the second and third samples in container B, and subsequent samples in container C (available for four radiologists from the first biopsy on). Technically successful biopsies and false-negative rate in three container combinations (A, A+B, A+B+C) were reported as a function of operator experience. Results: Technically unsuccessful biopsies occurred significantly more often in microcalcifications than in masses (14.9% versus 3.8%; P = 0.04). For microcalcifications, the rate of successful biopsies was 75% (18 24) for the first 5 biopsies and 87.8% (79 90) for the subsequent biopsies (P = 0.335); rates for the masses were 95.7% (22 23) and 96.3% (79 82) (P = 1.0), respectively. A tendency was noted for the false-negative rate to be higher for the first five biopsies in three container combinations than in subsequent cases. Conclusion: Our results support the existence of a learning curve, especially in the biopsy of microcalcifications. More than three mentor-guided biopsies are needed.