Performance Indices of Needle Biopsy Procedures for the Assessment of Screen Detected Abnormalities in Services Accredited by BreastScreen Australia


Background: We wished to analyse patterns of use of needle biopsy procedures by BreastScreen Australia(BSA) accredited programs to identify areas for improvement. Design: BSA services provided anonymous dataregarding percutaneous needle biopsy of screen detected lesions assessed between 2005-2009.
Results: 12 services,from 5 of 7 Australian states and territories provided data for 18212 lesions biopsied. Preoperative diagnosis rateswere 96.84% for lesion other than microcalcification (LOTM) and 93.21% for microcalcifications. At surgery97.9% impalpable lesions were removed at the first procedure. Of 11548 Microcalcification (LOTM) biopsied,46.9% were malignant. The final diagnosis was reached by conventional core biopsy (CCB) in 72.46%, FNAB in21.33%, VACB in 1.69% and open biopsy in 4.52% of lesions. FNA is being limited to LOTM with benign imagingAfter FNAB, core biopsy was required for 38% of LOTM. In LOTM the mean false positive rate (FPR) was0.36% for FNAB, 0.06% for NCB and 0% for VACB. Diagnostic accuracy was 72.75% for FNAB and 92.1% forcore biopsies combined. Of 6441 microcalcifications biopsied 2305 (35.8%) were malignant. Microcalcificationsare being assessed primarily by NCB but 6.57% underwent FNAB, 45.6% of which required NCB. False positivediagnoses were rare. FNR was 5% for NCB and 1.53% for VACB. Diagnostic accuracy was 73.52% for FNAB,86.29% for NCB and 88.63% for VACB. Only 8 of 12 services had access to VACB facilities.
Conclusions: BSAservices are selecting lesions effectively for biopsy and are achieving high preoperative diagnosis rates. Gaps inthe present accreditation standards require further consideration.