Not all nonpalpable breast cancers are alike.

Clinical and mammographic data of 1009 consecutive patients were correlated with histopathologic data of 1144 biopsy specimens of nonpalpable breast lesions to better define the presentation and biologic behavior of early breast cancer. Patients with malignant neoplasms (269 [24%] of 1144 specimens) were older (mean age, 62.1 years) than patients with benign lesions (mean age, 54.9 years). Furthermore, patients with invasive disease were older (mean age, 63.3 years) than patients with noninvasive disease (mean age, 58.5 years) with an overall increased risk of invasive cancer per year of 1.035. A 58% incidence of invasive cancer was detected for lesions characterized by calcifications, while the incidence of invasive cancer was 84% for isolated mass lesions (relative risk, 4.31 for masses). Isolated mammographic calcifications associated with cancer appeared in a younger population and were significantly associated with noninvasive ductal cancer. Breast cancer presenting as a mammographic mass appeared in an older group and was highly associated with the presence of invasive disease.