Rates of pathological underestimation for 9 and 12 gauge breast needle core biopsies at surgical excision

The clinical implementation of needle core biopsies has given radiologists an invaluable tool for the diagnostic evaluation of suspicious breast lesions. Despite improvements made to the technology of breast biopsy, the underestimation of disease in tissue samples retrieved continues. This can be attributed to many factors, including variability between different needle gauges. This study was undertaken to assess the pathological underestimation for 9 and 12 gauge breast needle core biopsies at surgical excision.

A retrospective review of image-guided consecutive core needle biopsies performed from 2003 to 2006 yielded a total of 1,201 needle core biopsies: 837 twelve gauge and 364 nine gauge. Further analysis was completed to distinguish needle biopsies whose pathological outcome was underestimated at core needle biopsy when compared to their subsequent surgical excision. Ninety-seven lesions in 88 patients were reviewed and comprise the study cohort.

Underestimation was found in 97 needle core procedures in 88 patients. Of the 97, 67 were performed with 12 gauge vacuum-assisted biopsy devices and 30 with 9 gauge vacuum-assisted biopsy devices, resulting in an underestimation rate of 8.00 and 8.24% for 12 gauge and 9 gauge, respectively. The difference in underestimation rate was not statistically significant per Pearson's chi squared test (P = 0.8898).

In this analysis, the underestimation of needle biopsy results with surgical pathology was found to be 8.00% for the 12 gauge group and 8.24% for the 9 gauge group. These results support our current clinical practice of utilizing either needle gauge.