What is a potential benefit of radiation therapy in cancer treatment?

Radiation therapy is often used in cancer treatment specifically to shrink tumors before surgery, making option A the most accurate choice. This preoperative treatment can decrease the size of a tumor, potentially making surgical removal easier and more effective. By reducing the tumor's dimensions, radiation therapy can also help to preserve surrounding healthy tissue and enhance the likelihood of a successful surgical outcome.

The other options present ideas that are not representative of common characteristics of radiation therapy. While radiation is indeed considered non-invasive, it is not typically without its complications or side effects, thus making that aspect not universally advantageous. Additionally, radiation is not always a single treatment; many patients may require multiple sessions, and its frequency depends on the specific cancer type and treatment plan. Finally, radiation therapy cannot prevent all types of cancer, as its primary role is in treatment rather than prevention. Hence, the benefit of shrinking tumors before surgery stands out as a critical aspect of its application in oncology.