Is combined tamoxifen plus hormonal therapy better for breast cancer?

No: Studies show that adding tamoxifen to an aromatase inhibitor (what i assume you mean by "hormonal therapy") was not better than either drug alone.

Tamoxifen only: For tumors that are estrogen positive, tamoxifen is the hormonal treatment for women that are premenopausal. If you are post menopausal, then aromatase inhibitors are the equivalent. We do not give additional hormones because the goal is to limit the amount of estrogen.