However, in cases of similar clinical presentation, adjuvant treatment confers similar benefits to black and white women. The decision of whether to recommend adjuvant hormone therapy should be based on the presence of hormone receptors, as assessed by immunohistochemical staining of breast cancer tissue. If the available tissue is insufficient to determine hormone receptor status, it should be considered positive. Women whose tumors lack hormone receptor protein but contain progesterone receptor may also benefit from hormone therapy. The NIH consensus panel believes that adjuvant hormone therapy should be recommended to all women whose breast tumors contain hormone receptor protein, but hormone therapy should not be administered to women whose cancer cells do not express hormone receptor protein.
Hormone therapy seeks to prevent breast cancer cells from receiving stimulation from estrogen.
Such stimulation occurs primarily in tumors that contain hormone receptor protein, so tumors that contain this protein may respond to hormone therapy. The most commonly used hormone therapy is tamoxifen, which may be used alone or in combination therapy. Trials indicate that five years of tamoxifen therapy are superior to one to two years of such treatment. Tamoxifen has been associated with an increased risk of endometrial cancer and venous thromboembolism, but in most women, the benefit of tamoxifen treatment far outweighs its risks. Ovarian ablation appears to produce a similar benefit to some chemotherapy regimens.