Which breast to biopsy: an expanding dilemma.

To provide insight into the significance of findings reported from screening asymptomatic women for breast cancer, we reviewed 19,928 mammographic studies with the accompanying physical examination and correlated these findings with 554 breast biopsies. Of 83 breast biopsies with suspicious findings on both physical examination and mammography, 72 demonstrated breast cancer (87%). Of 155 biopsies for suspicious changes on mammography alone, 50 (32%) demonstrated breast cancer. The accuracy of suspicious mammography was independent of findings limited to physical examination, 34 (17%) had breast cancer; 31 were in 152 biopsies of patients with mammography interpreted as normal (20%) and three were in biopsies of 52 patients (6%) in whom a visualized mass was interpreted as benign. One hundred and twelve breast biopsies were performed for changes interpreted as normal or benign. Six malignancies were discovered (5%). No cancer was found in 31 biopsies for nonpalpable benign mammographic abnormalities. Our results emphasize the importance of discriminating between nonvisualization of a mass and mammographic recognition of either a benign or malignant tumor. The reliability of interpretation is considerably greater for a visualized lesion than a nonvisualized one.