S-PHASE FRACTION AFTER GATING ON EPITHELIAL-CELLS PREDICTS RECURRENCEIN NODE-NEGATIVE BREAST-CANCER

We have compared the prediction of distant recurrence for S-phase frac tion (SPF) and DNA-ploidy, as estimated by flow cytometry, on an epith elial cell population and an unselected cell population from 268 node- negative breast-cancer patients diagnosed between 1985 and 1988. The t umor tissue was mechanically disintegrated and divided for flow cytome tric analysis using both gated cells containing cytokeratin 8 and 18 a nd ungated cells treated with a detergent-trypsin solution. The relati onship to distant recurrence was investigated for flow cytometric data , tumor size and estrogen and progesterone receptor content in univari ate and multivariate Cox's regression analysis. The regression analyse s were performed on 209 cases with S-phase fractions estimated by both methods. In 11 cases, DNA-ploidy classification differed, reflecting increased sensitivity to minor aneuploid peaks but a decreased ability to separate peaks in the near-diploid region for the gated population s. When SPF were used in univariate analysis as a continuous parameter or the upper tertile was used as cut-off value, SPF from the cytokera tin-gated cell population were most closely associated with recurrence and contributed additional prognostic information to SPF from the uns elected cell population in the multivariate analysis. Out of the follo wing variables:tumor size, ER and PR status, SPF and DNA ploidy, only SPF from immunoselected cells contributed prognostic information in mu ltivariate analysis. These results indicate that SPF from immunoselect ed cell populations improves the prediction of recurrence in node-nega tive breast cancer. (C) 1994 Wiley-Liss, Inc.