Stereotactic 14G core biopsy of non-palpable breast cancer: What is the relationship between the number of core samples taken and the sensitivity fordetection of malignancy?

AIM: Percutaneous 14-gauge core biopsy (CB) guided by digital stereotactic mammography is now an established technique in the investigation of women w ith non-palpable suspicious mammographic lesions. Diagnostic sensitivity of CB is affected both by the nature of the mammographic abnormality and by t he number of core samples taken. METHODS AND RESULTS: A retrospective review of 500 women who have undergone CB in our institution showed that in 235 cases, invasive or non-invasive c arcinoma was found on final surgical histology, Correlation between CB resu lt and surgical histology revealed a significant increase in sensitivity fo r the diagnosis of malignancy if a larger number of cores were taken (84.3% for two cores and 90.2% for five cores vs. 97.9% for six or more cores), T his trend was maintained when patients were subdivided according to mammogr aphic abnormality, either soft tissue mass or microcalcifications, The effe ct on diagnostic sensitivity of increasing the number of tissue cores obtai ned was most pronounced in patients with microcalcifications graded as low or moderately suspicious for malignancy (70.1% for two cores and 79.1% for five cores vs 94.0% for six or more cores), The presence of an invasive com ponent in a malignant lesion was correctly diagnosed using CB in 79.2% over all if at least six cores were taken. If the mammographic lesion was a soft tissue mass, this figure rose to 95.7%, but was only 35.7% if the visible lesion was composed of microcalcifications alone. CONCLUSION: Our series confirms the reliability of stereotactic CB in the d iagnosis of breast carcinoma, Diagnostic sensitivity is improved by increas ing the number of cores taken (to six or more), particularly in women with mammographic microcalcifications of an equivocal nature.