Table 3.
Relative risks associated with recurrence score among ER-positive patients, stratified by treatment with tamoxifen
| Score | Cases | Controls | RR1 | (95% CI) | P value | ||
| Tamoxifen treated (55 cases and 150 controls) | |||||||
| Recurrence Score | |||||||
| Continuous2 | 55 | (100%) | 150 | (100%) | 7.6 | (2.6–21.9) | <0.0001 |
| Pre-specified categories | |||||||
| Low risk (<18) | 16 | (29%) | 95 | (63%) | 1.0 | reference | |
| Intermediate risk (18–30) | 22 | (40%) | 35 | (23%) | 4.0 | (1.8–8.8) | |
| High risk (≥31) | 17 | (31%) | 20 | (13%) | 6.2 | (2.4–15.8) | |
| Quartiles3 | 0.0004 | ||||||
| 1st (0–8.25) | 5 | (9%) | 38 | (25%) | 1.0 | reference | |
| 2nd (8.26–14.43) | 6 | (11%) | 37 | (25%) | 1.0 | (0.3–3.7) | |
| 3rd (14.44–20.95) | 15 | (27%) | 38 | (25%) | 2.9 | (1.0–8.9) | |
| 4th (20.96–78.78) | 53 | (53%) | 37 | (25%) | 5.8 | (2.0–16.6) | |
| Tamoxifen untreated (110 cases and 251 controls) | |||||||
| Recurrence Score | |||||||
| Continuous2 | 110 | (100%) | 251 | (100%) | 4.1 | (2.1–8.1) | <0.0001 |
| Pre-specified categories | <0.0001 | ||||||
| Low risk (<18) | 40 | (36%) | 160 | (64%) | 1.0 | reference | |
| Intermediate risk (18–30) | 32 | (29%) | 47 | (19%) | 2.7 | (1.5–5.0) | |
| High risk (≥31) | 38 | (35%) | 44 | (18%) | 3.3 | (1.8–5.9) | |
| Quartiles4 | <0.0001 | ||||||
| 1st (0–7.53) | 11 | (10%) | 63 | (25%) | 1.0 | reference | |
| 2nd (7.54–14.25) | 19 | (17%) | 64 | (25%) | 1.5 | (0.7–3.4) | |
| 3rd (14.26–21.86) | 23 | (28%) | 62 | (25%) | 2.1 | (0.9–4.9) | |
| 4th (21.87–85.82) | 57 | (52%) | 62 | (25%) | 5.3 | (2.5-1.3) | |
1Conditional logistic regression models include Recurrence Score variables only. 2Relative risks for Recurrence Score calculated with regard to an increment of 50 units (chosen to be consistent with and comparable with previous studies). 3Quartiles based on distribution among controls treated with tamoxifen. 4Quartiles based on distribution among controls not treated with tamoxifen. CI, confidence interval; ER, estrogen receptor; RR, relative risk.