Table 2 Covariate adjusted interaction tests between tamoxifen treatment efficacy according to recurrence-free interval and different cell proliferation markers analyzed as binary factor. Co-variables included age (≥ 65 versus < 65), grade (grade 3 versus grade 1–2), tumor size (T3–4 versus T1-T2), HER2 status (positive versus negative), and PgR status (positive versus negative)
Variable | levels | HR (95% CI) for tamoxifen vs control (total follow-up) | Interaction p-value | HR (95% CI) for tamoxifen vs control (follow-up truncated at 6 yearsa) | Interaction p-value |
|---|---|---|---|---|---|
Mitotic count | <  8/ 2mm2 | 0.38 (0.20–0.70) | 0.13 | 0.24 (0.12–0.49) | 0.03 |
≥ 8/ 2mm2 | 0.70 (0.40–1.23) | 0.64 (0.35–1.17) | |||
Cyclin D1 | ≤ 50% | 0.48(0.25–0.93) | 0.48 |  | |
>  50% | 0.66 (0.34–1.29) | ||||
Ki67 | <  5% | 0.50 (0.26–0.98) | 0.97 | ||
≥ 5% | 0.50 (0.26–0.93) | ||||
CCND1 probeset 1 log 2copy number ratio | <  0 | 0.39 (0.18–0.86) | 0.33 | ||
>  0 | 0.62 (0.18–1.07) | ||||
CCND1 probeset 2 log2 copy number ratio | <  0 | 0.32 (0.16–0.61) | 0.04 | ||
>  0 | 0.81 (0.44–1.52) | ||||