Prognostic factors in node-negative breast cancer.

One hundred patients with node-negative breast cancer were examined to analyze the influence of tumor size, nuclear grade, and DNA content determined by flow cytometry on overall survival. Patients with diploid cancers lived significantly longer than those with aneuploid cancers (126 +/- 8 vs 80 +/- 11 months). Patients with an S-phase fraction less than 10% lived significantly longer than those with S-phase fractions 10% or greater (122 +/- 8 vs 85 +/- 10 months). Tumor size had the major impact on survival, and multivariate analysis of variance by the Cox proportional hazards model showed the greatest effect on prognosis. Tumor grade did not significantly influence overall survival.