Adjuvant therapy

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. 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. The term 'adjuvant therapy,' derived from the Latin term adjuvāre, meaning 'to help,' was first coined by Paul Carbone and his team at the National Cancer Institute in 1963. In 1968, the National Surgical Adjuvant Breast and Bowel Project (NSABP) published its B-01 trial results for the first randomized trial that evaluated the effect of an adjuvant alkylating agent in breast cancer. The results indicated that the adjuvant therapy given after the initial radical mastectomy 'significantly decreased recurrence rate in pre-menopausal women with four or more positive axillary lymph nodes.' The budding theory of using additional therapies to supplement primary surgery was put into practice by Gianni Bonadonna and his colleagues from the Instituto Tumori in Italy in 1973, where they conducted a randomized trial that demonstrated more favorable survival outcomes that accompanied use of Cyclophosphamide Methotrexate Fluorouracil (CMF) after the initial mastectomy. In 1976, shortly after Bonadonna's landmark trial, Bernard Fisher at the University of Pittsburgh initiated a similar randomized trial that compared the survival of breast cancer patients treated with radiation after the initial mastectomy to those who only received the surgery. His results, published in 1985, indicated increased disease-free survival for the former group. Despite the initial pushback from the breast cancer surgeons who believed that their radical mastectomies were sufficient in removing all traces of cancer, the success of Bonadonna's and Fisher's trials brought adjuvant therapy to the mainstream in oncology. Since then, the field of adjuvant therapy has greatly expanded to include a wide range of adjuvant therapies to include chemotherapy, immunotherapy, hormone therapy, and radiation. 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. In the context of breast cancer, neoadjuvant chemotherapy administered before surgery can improve survival in patients. If no active cancer cells are present in a tissue extracted from the tumor site after neoadjuvant therapy, physicians classify a case as “pathologic complete response” or 'pCR.' While response to therapy has been demonstrated to be a strong predictor of outcome, the medical community has still not reached a consensus in regard to the definition of pCR across various breast cancer subtypes. It remains unclear whether pCR can be used as a surrogate end point in breast cancer cases. 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.