Radiation therapy is a primary treatment for cancers that appear as solid tumors such as breast, lung, and pancreatic cancer. It has also been used to treat cancers of the blood, such as leukemia. Both high energy electromagnetic radiation and...

subatomic particles can destroy human cells. The energy from the radiation destroys some of the elements in the DNA and genetic machinery of cancer cells. When the cancer’s genetic material is disrupted or destroyed, it cannot make new cancer cells. Therefore when radiation therapy is administered, the tumor may stop growing because new cancer cells cannot form. Existing cancer cells may degenerate when exposed to this radiation as well. The goal of radiation therapy is to destroy cancer cells and prevent new cancer cells from forming.