Certified Tumor Registrar (CTR) Practice Exam

Immunotherapy is the correct answer, as it specifically involves the use of substances to stimulate or suppress the immune system in order to help the body fight diseases, particularly cancer. This type of therapy harnesses the body's natural defenses, enhancing the immune response against tumor cells or reducing inappropriate immune responses that may harm healthy tissues.

Immunotherapy can take various forms, including monoclonal antibodies, checkpoint inhibitors, and cancer vaccines, all aiming to boost the immune system's ability to recognize and destroy cancer cells. The goal of this therapy is to provide a targeted approach that can lead to long-lasting remission while often minimizing damage to healthy cells in contrast to other treatment modalities.

In the context of the other therapies mentioned, chemotherapy typically utilizes drugs to kill rapidly dividing cancer cells, but it does not mainly focus on manipulating the immune system. Radiation therapy targets cancer cells with high-energy radiation to destroy them directly, while hormonal therapy aims to interfere with hormone signals that can promote certain types of cancer growth, rather than directly engaging the immune system. Hence, immunotherapy uniquely emphasizes modulating immune responses, distinguishing it from other treatment strategies.