Adjuvant therapy in the context of "Radiation therapy"

Radiation therapy or radiotherapy (RT, RTx, or XRT) is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle accelerator. Radiation therapy may be curative in a number of types of cancer if they are localized to one area of the body, and have not spread to other parts. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor (for example, early stages of breast cancer). Radiation therapy is synergistic with chemotherapy, and has been used before, during, and after chemotherapy in susceptible cancers. The subspecialty of oncology concerned with radiotherapy is called radiation oncology. A physician who practices in this subspecialty is a radiation oncologist and practicing radiographer are therapeutic radiographer.

Radiation therapy is commonly applied to the cancerous tumor because of its ability to control cell growth. Ionizing radiation works by damaging the DNA of cancerous tissue leading to cellular death. To spare normal tissues (such as skin or organs which radiation must pass through to treat the tumor), shaped radiation beams are aimed from several angles of exposure to intersect at the tumor, providing a much larger absorbed dose there than in the surrounding healthy tissue. Besides the tumor itself, the radiation fields may also include the draining lymph nodes if they are clinically or radiologically involved with the tumor, or if there is thought to be a risk of subclinical malignant spread. It is necessary to include a margin of normal tissue around the tumor to allow for uncertainties in daily set-up and internal tumor motion. These uncertainties can be caused by internal movement (for example, respiration and bladder filling) and movement of external skin marks relative to the tumor position.

In pharmacology, an adjuvant is a drug or other substance, or a combination of substances, that is used to increase the efficacy or potency of certain drugs. Specifically, the term can refer to:

• Adjuvant therapy in cancer management
• Analgesic adjuvant in pain management
• Immunologic adjuvant in vaccines

Breast cancer management takes different approaches depending on physical and biological characteristics of the disease, as well as the age, over-all health and personal preferences of the patient. Treatment types can be classified into local therapy (surgery and radiotherapy) and systemic treatment (chemo-, endocrine, and targeted therapies). Local therapy is most efficacious in early stage breast cancer, while systemic therapy is generally justified in advanced and metastatic disease, or in diseases with specific phenotypes.

Historically, breast cancer was treated with radical surgery alone. Advances in the understanding of the natural course of breast cancer as well as the development of systemic therapies allowed for the use of breast-conserving surgeries, however, the nomenclature of viewing non-surgical management from the viewpoint of the definitive surgery lends to two adjectives connected with treatment timelines: adjuvant (after surgery) and neoadjuvant (before surgery).