PROGNOSTIC-SIGNIFICANCE OF PROLIFERATIVE ACTIVITY AND PLOIDY IN NODE-NEGATIVE BREAST CANCERS

Background: Cell kinetics and DNA ploidy have provided relevant information on the natural history of breast cancer. We assessed the prognostic role of proliferative activity and ploidy, alone and in association with tumor size, estrogen (ER) and progesterone (PgR) receptors. Patients and methods: In a series of 340 women with resectable node-negative breast cancers given local-regional therapy alone until relapse, proliferative activity was determined as the H-3-thymidine labeling index (H-3-dT 1.1) and flow-cytometric S-phase, cell fraction (FCM-S), as quantified by using different modeling systems, DNA ploidy, ER and PgR content were determined on frozen samples by FCM and by the dextran-coated charcoal absorption technique, respectively. Results: FCM-S estimates obtained by the different models were weakly associated with one another and to the corresponding H-3-dT LIs. Four-year relapse-free survival was significantly predicted by H-3-dT LI, ploidy and tumor size but not by FCM-S. Multiple regression analysis showed that H-3-dT LI, ploidy and tumor size retained their prognostic significance and that H-3-dT LI was the most significant indicator of relapse (p=0.009). Conclusions: The finding that H-3-dT LI and ploidy are weakly related and provide independent prognostic information could allow a more accurate identification of patients at different risk of relapse.