A. Complete trial population |

All patients |

Overall follow-up (events: *n* = 242) |

Placebo (*n* = 134) | 1 | 0.076 |

Tamoxifen (*n* = 108) | 0.80 (0.62–1.02) | |

During treatment period (events: *n* = 93) |

Placebo (*n* = 49) | 1 | 0.589 |

Tamoxifen (*n* = 44) | 0.89 (0.60–1.34) | |

Posttreatment period (events: *n* = 149) |

Placebo (*n* = 85) | 1 | 0.067 |

Tamoxifen (*n* = 64) | 0.74 (0.53–1.02) | |

ER-positive |

Overall follow-up (events: *n* = 187) |

Placebo (*n* = 108) | 1 | 0.028 |

Tamoxifen (*n* = 79) | 0.72 (0.54–0.97) | |

During treatment period (events: *n* = 75) |

Placebo (*n* = 42) | 1 | 0.290 |

Tamoxifen (*n* = 33) | 0.78 (0.50–1.23) | |

Posttreatment period (events: *n* = 112) |

Placebo (*n* = 66) | 1 | 0.048 |

Tamoxifen (*n* = 46) | 0.68 (0.47–0.996) | |

B. IHC subset |

Overall follow-up (*n* = 179) |

Placebo (*n* = 100) | 1 | 0.100 |

Tamoxifen (*n* = 79) | 0.78 (0.58–1.05) | |

ER-positive (*n* = 139) |

Placebo (*n* = 85) | 1 | 0.007 |

Tamoxifen (*n* = 54) | 0.63 (0.45–0.88) | |

ER-negative (events: *n* = 40) |

Placebo (*n* = 15) | 1 | 0.127 |

Tamoxifen (*n* = 25) | 1.65 (0.87–3.12) | |