Stereotactic breast biopsy of nonpalpable lesions: Determinants of ductal carcinoma in situ underestimation rates

PURPOSE: To measure the effect of biopsy device, probe size, mammographic l esion type, lesion size, and number of samples obtained per lesion on the d uctal carcinoma in situ (DCIS) underestimation rate. MATERIALS AND METHODS: Nonpalpable breast lesions at 16 institutions receiv ed a histologic diagnosis of DCIS after 14-gauge automated large-core biops y in 373 lesions and after 14- or 11-gauge directional vacuum-assisted biop sy in 953 lesions. The presence of histopathologic invasive carcinoma was n oted at subsequent surgical biopsy. RESULTS: By performing the chi (2) test, independent significant DCIS under estimation rates by biopsy device were 20.4% (76 of 373) of lesions diagnos ed at large-core biopsy and 11.2% (107 of 953) of lesions diagnosed at vacu um-assisted biopsy (P < .001); by lesion type, 24.3% (35 of 144) of masses and 12.5% (148 of 1,182) of microcalcifications (P < .001); and by number o f specimens per lesion, 17.5% (88 of 502) with 10 or fewer specimens and 11 .5% (92 of 799) with greater than 10 (P < .02). DCIS underestimations incre ased with lesion size. CONCLUSION: DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more frequent with large-core biopsy th an with vacuum-assisted biopsy, and 1.5 times more frequent with 10 or fewe r specimens per lesion than with more than 10 specimens per lesion.