How long after lumpectomy for DCIS in a premenopausal patient can tamoxifen be started and still retain the benefit?

The TAM-02 trial showed that women with IDC who delayed taking tamoxifen 2 or more years after their diagnosis still did better than those who did not initiate it at all. You can extrapolate this data to ER+ DCIS as the protective benefit of estrogen blockade on breast tissue occurs whenever it is s...