Adjuvant systemic therapy refers to additional drug treatments given because of the possibility that cancer has spread to other parts the body. The appropriate drug treatments for adjuvant therapy depend primarily on whether the cancer carries a protein called the “estrogen receptor” or the “progesterone receptor” (hormone receptor positive). If these proteins are present, then the woman benefits from taking an anti-estrogen endocrine drug (tamoxifen in pre-menopausal women and an aromatase inhibitor such as anastrozole in post-menopausal women) for at least 5 years. This may be combined with chemotherapy based on the size of the cancer, the involvement of lymph nodes, and the microscopic and genomic appearance of the cancer. For women whose cancers are hormone receptor negative, the anti-estrogen pills are not useful, and the only choice is chemotherapy. Some women, such as those with very small or otherwise favorable cancers, may not need any drug treatments.
Hormone Receptor Positive
These graphs show the proportion of women by stage with hormone receptor positive cancer who received adjuvant endocrine (hormone) therapy, chemotherapy, both or neither by stage in 2009.