The major objectives of this prospective study were to compare pathologic findings from stereotaxic core and excisional biopsies performed on patients with impalpable breast lesions and to compare the initial mammographic impression with the final histologic diagnosis.
All patients referred for preoperative localization of impalpable breast lesions between October 29, 1991, and January 15, 1993, were eligible for the study. If the patient and the lesion, on the basis of mammography, were considered suitable for core biopsy, the patient was asked to participate. Four hundred forty-five excisional biopsies were performed. One hundred sixty lesions were evaluated by core biopsy; for 104 of these lesions, five or more core samples were removed. Core biopsies were done with 14-gauge biopsy needles and were followed by a localization procedure. The pathologic features of core and excisional specimens were compared.
Biopsy results were compared for 93 (58%) benign and 67 (42%) malignant lesions. Of 104 lesions evaluated with at least five core specimens, 56 (54%) were benign and 48 (46%) were malignant. Results of core biopsy corresponded to those of excisional biopsy for 96% of benign lesions, 83% of malignant lesions, and 90% overall; sensitivity of core biopsy for malignant lesions was 85%. Of 56 lesions for which fewer than five core specimens were obtained, 37 (66%) were benign and 19 (34%) were malignant. Results of core biopsy corresponded to those of excisional biopsy for 81% of benign lesions, 79% of malignant lesions, and 80% overall; sensitivity of core biopsy for malignant lesions was 84%. Specificity of core biopsy for the entire series of benign lesions was 100%.
For mammographic lesions that are believed to be not malignant or not very likely malignant, stereotaxic core biopsy decreases the need for excisional biopsy.