What is the primary purpose of radiation therapy in cancer treatment?

The primary purpose of radiation therapy in cancer treatment is to damage the DNA of tumor cells. This approach is essential because cancer cells typically grow and divide more rapidly than normal cells, and damaging their DNA can lead to cell death or inhibit their ability to reproduce. By targeting the genetic material, radiation therapy aims to disrupt the cancer's growth process while sparing as much healthy tissue as possible. This mechanism is fundamental to successfully shrinking tumors, reducing cancer symptoms, and improving the overall treatment outcome.

The other options present different concepts that are not aligned with the primary goal of radiation therapy. While enhancing appetite may be a beneficial side effect of some treatments, it is not a purpose of radiation therapy. Preventing surgery could be a consideration based on specific circumstances or treatment plans, but it does not define the role of radiation. Additionally, eliminating all forms of cancer is an unrealistic goal; while radiation can significantly reduce or control tumors, it is not always curative, especially in advanced stages of cancer.