Less is known about the role of proliferative cellular activity, and the expression of tumor promoting and suppressing oncogenes. Presence of hormonal receptor proteins dectectable on tumor cell surfaces indicates hormonal treatment should be offered. The goal is to prevent tumor cells from estrogen stimulation. Tamoxifen blocks estrogen receptors. Suppression of estrogen synthesis is achieved in postmenopausal women with aromatase inhibitors.
Tamoxifen has estrogenic effects on bone, endometrium, liver.
5 years is the standard duration of therapy based on current information. The majority of women with localized breast cancer greater than 1 cm. should be offered polychemotherapy. Chemotherapy has been shown to improve overall survival, relapse free survival and long term survival in pre-menopausal women, postmenopausal women up to the age of 70, and in both node negative and node positive disease. The consensus conference found no use for post-chemotherapy treatment, but some practitioners disagree. Herceptin is currently being studied.