A population-based study of tumor gene expression and risk of breast cancer death among lymph node-negative patients

Table 4 Relative risks of breast cancer death associated with tumor size, grade, and recurrence score among ER-positive patients, stratified by treatment with tamoxifen

Score	Cases		Controls		RR	95% CI	P value
Tamoxifen treated (55 cases and 150 controls)
Multivariate analyses without Recurrence Score¹
Tumor size (cm)							0.009
Continuous²	55	(100%)	150	(100%)	2.6	(1.2–5.5)
Grade (pathologist 1)							0.007
Well	6	(11%)	50	(33%)	1.0	reference
Moderate	28	(51%)	69	(46%)	2.8	(1.1–7.4)
Poor	21	(38%)	31	(21%)	4.5	(1.6–12.3)
Multivariate analyses with Recurrence Score³
Tumor size (cm)							0.013
Continuous²	55	(100%)	150	(100%)	2.5	(1.2–5.4)
Grade (pathologist 1)							0.126
Well	6	(11%)	50	(33%)	1.0	reference
Moderate	28	(51%)	69	(46%)	2.4	(0.9–6.4)
Poor	21	(38%)	31	(21%)	2.8	(0.9–9.3)
Recurrence Score							0.003
Continuous⁴	55	(100%)	150	(100%)	5.3	(1.6–17.2)
Tamoxifen untreated (110 cases and 251 controls)
Multivariate analyses without Recurrence Score¹
Tumor size (cm)							0.035
Continuous²	110	(100%)	251	(100%)	1.8	(1.0–3.1)
Grade (pathologist 1)							<0.001
Well	17	(15%)	83	(33%)	1.0	reference
Moderate	54	(49%)	131	(52%)	2.0	(1.1–3.6)
Poor	39	(35%)	37	(15%)	4.7	(2.3–9.9)
Multivariate analyses with Recurrence Score³
Tumor size (cm)							0.036
Continuous²	110	(100%)	251	(100%)	1.8	(1.0–3.1)
Grade (pathologist 1)							0.018
Well	17	(15%)	83	(33%)	1.0	reference
Moderate	54	(49%)	131	(52%)	1.8	(1.0–3.4)
Poor	39	(35%)	37	(15%)	3.2	(1.4–7.2)
Recurrence Score							0.025
Continuous⁴	110	(100%)	251	(100%)	2.4	(1.1–5.2)

¹Conditional logistic regression models include tumor size and tumor grade only. ²Relative risks for tumor size calculated with regard to an increment of 2 cm. ³Conditional logistic regression models include tumor size, tumor grade, and Recurrence Score. ⁴Relative risks for Recurrence Score calculated with regard to an increment of 50 units (chosen to be consistent with and comparable to previous studies). CI, confidence interval; ER, estrogen receptor; RR, relative risk.

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