DNA flow cytometry in node-positive breast cancer: Prognostic value and correlation with morphologic and clinical factors

OBJECTIVE: To help clarify the possible usefulness of nuclear DNA content and S-phase fraction (SPF) as additional prognostic factors in node-positive breast cancer patients because there is increased interest in the development of new factors that might provide more detailed prognostic information. STUDY DESIGN: We performed a DNA and SPF analysis by flow cytometry using a multivariate statistical model on a group of 139 node-positive breast cancer patients with clearly defined inclusion and exclusion criteria. RESULTS: The percentage of aneuploidy increased with the number of involved nodes. Aneuploid tumors were more often found among grade 3 and among receptor- negative tumors. Univariate analysis showed a strong effect on recurrence free survival (RFS) for the number of involved nodes (P < .001) and for tumor size (P = .013). Grade 3 and receptor-negative tumors showed a nonsignificant trend toward increased risk. The relative risk of aneuploid tumors was 1.19 (95% confidence interval, 0.75-1.87). Multivariate analysis revealed only the number of involved nodes to be an independent prognostic factor (P = .002); ploidy showed no effect (P = .684). SPF did not show any significant effect on RFS, even in a univariate analysis. CONCLUSION: These results suggest that nuclear DNA content and SPF correlate with morphologic factors. Their routine clinical use, however, in node positive breast cancer patients receiving adjuvant therapy seems to have no clinical relevance and therefore can be omitted.