Learning curve for stereotactic breast biopsy: How many cases are enough?

OBJECTIVE. The objective of this study was to evaluate the learning curve f or stereotactic breast biopsy. MATERIALS AND METHODS. Retrospective review was performed of 923 consecutiv e lesions that underwent stereotactic breast biopsy performed by one of six radiologists. Four hundred fourteen lesions had 14-gauge automated core bi opsy, and 509 subsequent lesions had vacuum-assisted biopsy (14-gauge in 16 3 and 11-gauge in 346). Medical records were reviewed to determine the tech nical success rate and false-negative rate as a function of operator experi ence. RESULTS. For 14-gauge automated core biopsy. a significantly lower technica l success rats was seen for the first five cases of each radiologist than f or subsequent cases (25/30 = 83.3% versus 366/384 = 95.3%. p < 0.02) and fo r the first 20 cases than for subsequent cases (90/100 = 90% versus 284/296 = 95.9%. p < 0.05). For 11-gauge vacuum-assisted biopsy. a significantly l ower technical success rate was seen for the first five cases than fur subs equent cases (17/20 = 85.0% versus 310/322 = 96.3%. p < 0.05) and for the f irst 15 cases than for subsequent cases (54/60 = 90.0% versus 273/283 = 96. 5%. p = 0.03). The false-negative rate was higher for the: first 15 cases c ompared with subsequent cases both fur stereotactic 14-gauge automated core biopsy (4/31 = 12.9% versus 3/115 = 2.6%, p < 0.04) and for stereotactic I i-gauge vacuum-assisted biopsy (2/27 = 7.4%; versus 0/85 = 0%, p < 0.06). CONCLUSION. A learning curve exists for stereotactic breast biopsy. Signifi cantly higher technical success rates and lower false-negative rates were o bserved after the first five to 20 cases fur 14-gauge automated core biopsy and after the first five to 15 casts for 11-gauge vacuum-assisted biopsy. Even after a radiologist has experience with stereotactic biopsy. changes i n equipment may result in a new learning curve.