Stereotactic core needle biopsy in non-palpable breast lesions. What number is needed?

Purpose: To investigate whether three stereotactic core needle biopsies (S-CNB) in non-palpable breast lesion are enough for accurate preoperative diagnosis.

Material And Methods: Between September 1994 and December 2000, 523 patients with mammographically detected breast lesions and who proceeded to surgery were preoperatively stereotactically biopsied with an automated 14-gauge biopsy device. Three samples were taken from each lesion irrespective of whether the lesion presented as "microcalcifications only", "microcalcifications and a mass", or a "mass, architectural distorsion, or stellate lesion without microcalcifications". The histopathology was divided into three subgroups: diagnostic, atypia (ranging from atypical cells to probably cancer), and non-diagnostic material.

Results: Post-surgical histopathology diagnosed 454 (87%) malignant tumors and 69 (13%) benign lesions. Three S-CNB correctly diagnosed the malignant tumors in 84% in the subgroup "microcalcifications only". In the category "microcalcifications and a mass", the diagnostic accuracy was 97% and in the subgroup "mass, architectural distorsion, or stellate lesion without microcalcifications" 3 S-CNB resulted in 93% correct diagnostic material. In 19 of the 454 patients (4%) 1, 2 or all 3 preoperative S-CNB showed atypia. In 20 patients (4%), all 3 S-CNB were non-diagnostic. Thirteen of these 20 patients had "microcalcifications only" and 7 had a mass without microcalcifications.

Conclusion: Three S-CNB were enough for correct diagnosis in "masses, architectural distorsions, or stellate lesions without microcalcifications" and in "microcalcifications and a mass", but were not sufficient in "microcalcifications only".