Adjuvant: Adjuvant is a term for describing a form of treatment in which the idea is to prevent the recurrence of cancer. For example breast cancer patients who had surgery for the tumor may be offered adjuvant chemotherapy and adjuvant radiation therapy, even though there is no evidence of breast in that patient. Adjuvant therapy is aimed at decreasing the risk of cancer recurrence. See breast cancer treatment page for details on adjuvant therapy of breast cancer. See cancer terms for more cancer related terms.