Adjuvant therapy, also known as adjunct therapy, add-on therapy, and adjuvant care, is therapy that is given in addition to the primary or initial therapy to maximize its effectiveness. The surgeries and complex treatment regimens used in cancer therapy have led the term to be used mainly to describe adjuvant cancer treatments. An example of such adjuvant therapy is the additional treatment usually given after surgery where all detectable disease has been removed, but where there remains a statistical risk of relapse due to the presence of undetected disease. If known disease is left behind following surgery, then further treatment is not technically adjuvant.
An adjuvant agent modifies the effect of another agent, so adjuvant therapy modifies other therapy.
Neoadjuvant therapy, in contrast to adjuvant therapy, is given before the main treatment. For example, systemic therapy for breast cancer that is given before removal of a breast is considered neoadjuvant chemotherapy. The most common reason for neoadjuvant therapy for cancer is to reduce the size of the tumor so as to facilitate more effective surgery.
For example, radiotherapy or systemic therapy is commonly given as adjuvant treatment after surgery for breast cancer. Systemic therapy consists of chemotherapy, immunotherapy or biological response modifiers or hormone therapy.Oncologists use statistical evidence to assess the risk of disease relapse before deciding on the specific adjuvant therapy. The aim of adjuvant treatment is to improve disease-specific symptoms and overall survival. Because the treatment is essentially for a risk, rather than for provable disease, it is accepted that a proportion of patients who receive adjuvant therapy will already have been cured by their primary surgery.
Adjuvant systemic therapy and radiotherapy are often given following surgery for many types of cancer, including colon cancer, lung cancer, pancreatic cancer, breast cancer, prostate cancer, and some gynaecological cancers. Some forms of cancer fail to benefit from adjuvant therapy, however. Such cancers include renal cell carcinoma, and certain forms of brain cancer.