The significance of new densities and microcalcification in the second round of breast screening

Abstract

AIM: To assess the nature of new densities and microcalcifications in the second round of breast screening. MATERIALS AND METHODS: A total of 34 634 women were screened at our unit in the second round of the United Kingdom National Health Service Breast Screening Programme. Of those attending for the second time, 302 were recalled for further work-up of 311 new lesions. The lesions were divided into masses, microcalcifications, asymmetric densities and architectural distortions. Masses were classified according to margin and density, and microcalcifications according to morphology and distribution. RESULTS: Among women attending for the second time, the cancer detection rate was 0.45% (89 cancers). One hundred and eighty-eight new masses were identified: 53 well-defined (two malignant), 67 partially defined (six malignant), 54 ill-defined (18 malignant), and 14 spiculate (14 malignant). Well-defined masses were usually cysts, especially in women on hormone replacement therapy. Of 97 new microcalcifications, 71 were pleomorphic (28 malignant), 12 linear (one malignant), and 14 punctate (none malignant). Twenty-five new asymmetric densities were identified (five malignant). One of two architectural distortions was malignant. Malignancy was found in 21% of new masses, 30% of new microcalcification and 20% of asymmetric densities. CONCLUSION: Carcinoma was found in 24% of all new mammographic abnormalities appearing in a 3-year screening period. Spiculate and ill-defined masses, clustered pleomorphic microcalcification, and new asymmetric densities should be regarded with particular suspicion. The use of fine needle aspiration cytology in combination with imaging assessment may help to reduce the number of benign excisional biopsies for new mammographic lesions.