Variation of flow cytometric DNA measurement in 1,485 primary breast carcinomas according to guidelines for DNA histogram interpretation

From 1990–1996, 1,485 previously untreated invasive breast carcinomas were sampled by a pathologist for flow cytometric DNA analysis. The aim of the present work was to study the variations of flow cytometric DNA ploidy and S‐phase evaluation according to the conditions of DNA histogram interpretation. Results obtained with the American Consensus guidelines of 1993 and the François Baclesse Department of Pathology's own guidelines are presented. According to the percentage of events taken into account to identify a DNA aneuploid peak, the proportion of DNA diploid cases can change from 35–39%. For S‐phase evaluation, although the two guidelines were quite different, the results of S‐phase cutoff were identical. Whichever guidelines were used, there was a strong relationship between DNA ploidy and/or S‐phase and classical clinicopathological factors (T, N, histological type, grade, receptor status, or lymphatic invasion), with the exception of age, whose correlation was discrepant with S phase according to the set of guidelines. Whichever guidelines were used, ploidy and S phase correlated strongly with survival (overall, metastasis‐free, or recurrence‐free). Hence we recommend the use of the American consensus guidelines, despite minor imperfections, because they are now well‐known, allow a high yield in the ratio of assessable S phases, and permit standardization in the technical processing and reporting of S phases, thanks to the use of terciles.Cytometry (Comm. Clin. Cytometry) 42:35–42, 2000 © 2000 Wiley‐Liss, Inc.