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.