Table 3.

Cox Proportional Hazards Regression Model^a assessing interaction of recurrence score (RS) risk group (Grouping Method I) with chemotherapy effect, excluding patients with presumed HER2-positive disease

n = 564 patients
Effect	Hazard ratio (95% Confidence interval)	Likelihood ratio test on interaction, P value
Chemotherapy in RS ≤ 10	1.19 (0.41–3.51)	0.014
Chemotherapy in RS from 11–25	0.61 (0.26–1.35)
Chemotherapy in RS > 25	0.27 (0.12–0.62)

^a Adjusting for patient age (>50 vs. ≤50 years), clinical tumor size (>2.0 vs. ≤2.0 cm), ER by ligand binding assay (≥100 vs. <100 fmol/mg), PR by ligand binding assay (≥100 vs. <100 fmol/mg), and tumor grade (well differentiated, moderately differentiated, and poorly differentiated). Five (5) patients had missing values in tumor grade or tumor size.