Breast biopsy with needle localization: influence of age and mammographic feature on the rate of malignancy in 350 nonpalpable breast lesions.

The purpose of this study was to determine the influence of mammographic feature and patient age on the rate of malignancy in nonpalpable breast lesions. During a 3-year period, 305 patients underwent biopsy after needle localization of 350 nonpalpable breast lesions. A total of 66 malignant breast tumors were found (biopsy yield rate, 19%): 23 carcinoma in situ, 43 infiltrating cancer. The biopsy yield rate in women younger than 50 years was 8% (12 of 153) and in women 50 years or older 27% (54 of 197; p less than 0.001). The biopsy yield rate varied with the mammographic feature in both groups of patients and was highest for spicular masses (61%), followed by strongly suspicious calcifications (29%). No cancers were found among well-defined masses or asymmetric densities. Other factors that were associated with high biopsy yield rate were personal or family history of breast cancer and diagnostic, rather than screening, mammography. The results suggest that the rate of malignancy in nonpalpable breast lesions is influenced by several factors, including age of patient and mammographic feature of the lesion. By taking all these factors into account, biopsies can possibly be performed more selectively thereby increasing the cost effectiveness of biopsy for occult breast cancer.