In these cases if the level of hormones that reaches the cancer cells is decreased, then the cells may stop growing and die. Whether your cancer is affected by hormones can be determined by hormone receptor tests. When your tumor is removed, your doctor will perform estrogen and progesterone receptor tests on a tissue sample. These tests show whether the tumor has hormone receptors. Hormone therapy seeks to prevent breast cancer cells from receiving stimulation from estrogen.
Tamoxifen is the most commonly used type of hormone therapy.
Once a breast cancer cell accepts tamoxifen in the place of true estrogen, the cell is no longer able to receive the estrogen that it needs to divide. Eventually, it stops growing and dies. Tamoxifen is taken daily in pill form, usually for 5 years. Because the drug doesn't distinguish between cancer and normal cells, some normal cells will be affected. Slight long-term increased risk of uterine cancer Hormone therapy is recommended only for women whose tumors are hormone receptor positive or are of unknown status.