Table 1.
Association of the Continuous Recurrence Score With Distant Recurrence Risk From 0 to 5 Years and After 5 Years According to ESR1 Expression in B-28 and B-14, on the Basis of Cox Proportional Hazards Models
| ESR1 Expression Group | 0 to 5 Years | After 5 Years | ||||||
|---|---|---|---|---|---|---|---|---|
| No. | Events | HR (95% CI)* | P* | No.† | Events | HR (95% CI)* | P* | |
| NSABP B-28 ER-positive patients (n = 1,065) | ||||||||
| All patients | 1,065 | 191 | 4.22 (2.93 to 6.07) | < .001 | 832 | 168 | 1.66 (1.05 to 2.61) | .04 |
| ESR1 ≤ 9.1 | 355 | 75 | 5.86 (3.18 to 10.80) | < .001 | 266 | 52 | 0.85 (0.36 to 2.00) | .70 |
| ESR1 > 9.1 | 710 | 116 | 3.46 (2.09 to 5.71) | < .001 | 566 | 116 | 2.43 (1.42 to 4.18) | .003 |
| NSABP B-14 tamoxifen-treated patients (n = 668) | ||||||||
| All patients | 668 | 59 | 6.04 (3.88 to 9.41) | < .001 | 564 | 50 | 1.55 (0.81 to 2.97) | .20 |
| ESR1 ≤ 9.1 | 91 | 19 | 4.29 (1.86 to 9.89) | < .001 | 67 | 6 | 0.21 (0.02 to 2.33) | .14 |
| ESR1 > 9.1 | 577 | 40 | 5.85 (3.23 to 10.60) | < .001 | 497 | 44 | 2.23 (1.11 to 4.47) | .04 |
Abbreviations: ER, estrogen receptor; HR, hazard ratio; NSABP, National Surgical Adjuvant Breast and Bowel Project; RS, recurrence score.
On the basis of Cox proportional hazards models that include the RS with time dependence (all patients’ results) or the RS, ER group indicator, the RS by ER interaction, and time dependence for each parameter (ESR1 expression group results). RS HRs are presented for a 50-point difference. P values are from likelihood ratio tests; CIs use the Wald method. Interaction P values were not the primary basis of cut point selection or testing but were as follows: RS × ESR1 expression group after 5 years: P = .04 (B-28) and P = .03 (B-14). RS × ESR1 expression group 0 to 5 years: P = .19 (B-28) and P = .35 (B-14). The interactions after 5 years remained significant (P < .05) when adjusting for age, nodal status (B-28 only), grade, and size in the models.
Patients at risk at 5 years.