What is the term for a group of treatments designed to enhance the body's natural defense against cancer?

The term that best fits the description of a group of treatments designed to enhance the body's natural defense against cancer is immunotherapy. Immunotherapy works by stimulating the immune system to recognize and destroy cancer cells more effectively. While biologic response modifiers can be considered part of immunotherapy, the broader category specifically focused on enhancing the body’s immune response is classified as immunotherapy.

Chemotherapy refers to the use of drugs to kill fast-growing cancer cells but does not specifically enhance the immune system's natural defenses. Targeted therapy, on the other hand, focuses on specific characteristics of cancer cells, such as mutations in DNA, rather than enhancing the body’s immune response.

Understanding these distinctions is crucial for effectively categorizing cancer treatments and recognizing the varying mechanisms by which they operate. Therefore, the correct answer aligns with the focus on treatments that specifically enhance the immune system's ability to fight cancer.