Complete percutaneous excision of infiltrating carcinoma at stereotactic breast biopsy: How can tumor size be assessed?

OBJECTIVE, The purpose of this study was to determine the frequency of comp lete excision of infiltrating carcinoma at stereotactic Ii-gauge directiona l vacuum-assisted breast biopsy and to evaluate the feasibility of measurin g tumor size in stereotactic biopsy specimens in infiltrating carcinomas th at were percutaneously excised. MATERIALS AND METHODS. We performed retrospective review of 51 infiltrating carcinomas diagnosed using stereotactic Ii-gauge directional vacuum-assist ed biopsy that underwent subsequent surgery. For lesions yielding no residu al infiltrating carcinoma at surgery, the maximal dimension of the tumor wa s measured in stereotactic biopsy specimens using ocular micrometry. RESULTS. In 10 (20%) (95% confidence intervals, 9.8-33.1%) of 51 infiltrati ng carcinomas diagnosed at stereotactic biopsy surgery revealed no residual infiltrating carcinoma. Complete excision of infiltrating carcinoma was mo re frequent if 14 or more specimens were obtained (32% versus 0%,p < .004), if the mammographic lesion was removed (35% versus 7%, p < .03), and if th e mammographic lesion size measured 0.7 cm or less (50% versus 16%, p = .08 ). Tumor size in stereotactic biopsy specimens was within 3 mm of mammograp hic lesion size in six (60%) of 10 lesions, including five (71%) of seven m asses and one (33%) of three calcification lesions, but was smaller than th e mammographic lesion size in eight (80%) of 10 lesions. CONCLUSION. Surgery revealed no residual infiltrating carcinoma in 10 (20%) of 51 infiltrating carcinomas diagnosed at stereotactic 11-gauge biopsy. A lthough tumor size can be assessed in stereotactic biopsy specimens in thes e lesions, such measurements may underestimate the maximal dimension of the tumor. Further study is needed to evaluate the usefulness of these measure ments in guiding treatment decisions.