Image cytometry in nonproliferative fibrocystic breast changes. Ploidy evaluation and epidemiologic study

To determine the usefulness of image cytometry on fine needle aspirates from patients with fibrocystic changes (FCCs) to assess the subsequent risk of breast cancer.

Thirty-five hundred archival cases with fine needle aspiration (FNA) biopsy were assessed to select nonproliferative FCCs of the breast (500 cases), also classified as type 1 (FCC I). DNA evaluation was analyzed by means of image cytometry on ductal epithelial cells and on apocrine metaplastic cells; 97 quantifications were performed. Cytometric variables investigated were: DNA ploidy, G0/G1 peak of diploid nuclei, S-phase fraction, 5cER, 2cDI and coefficient of variation. Two groups each with 15 years of follow-up were formed: Simple pathology (SP), fibrocystic changes alone; associated pathology (AP), FCCs plus breast cancer. Each was studied separately and compared.

In SP cases the average ploidy was 2.2 for epithelial cells and 4.2 for apocrine cells. The proportion of G0G1 diploid nuclei was 100%. In the study of AP, the average ploidy was 2.2 for epithelial ductal cells and 4.1 for apocrine ones, for a slight increase in SPF. Ductal cells were diploid, while apocrine cells were tetraploid, with statistical significance of P < .05. For the epidemiologic study we calculated the proportion of patients with FCC I who developed cancer by referring to a historical cohort study, obtaining a relative risk of 0.7.

Our results prove that DNA image cytometry applied on FNA cytology is a very useful, minimally invasive and reliable tool to determine higher activity and risk for development of breast cancer in FCC I and thus to establish the need for closer follow-up of these patients. In addition, apocrine metaplastic cells of the breast display a tetraploid DNA histogram, while the other karyometric variables remain in the range of normality.