Radiation is a treatment designed to target and kill cancerous cells that are dividing uncontrollably in the body. Radiation can originate externally from a machine administering radiation, or internally from a radioactive substance injected into the body, notes the National Cancer Institute.
Cancer Cell Death
The main task of any radiation therapy for cancer is to kill as many cancerous cells as possible, according to the American Cancer Society. All normal cells go through a similar life cycle: they are created, function in cell processes, and then die as new cells are generated to replace them. Cancer cells do not follow the same life cycle as regular cells. In fact, cancerous cells will continue to divide and make more cancerous cells if they aren't stopped. The best case scenario during radiation is to end the life cycle of these cells as the cell biology originally intended.
Cancer Cell Impairment
Radiation therapy is not an especially precise procedure. Waves of radiation are concentrated on the cancerous growth with the goal of killing off the cells, but other outcomes are possible. In some instances, the radiation may cause irreversible DNA damage that can thwart growth without killing the cell. The radiation dose can cause mutations randomly throughout the genome of the damaged cell causing a variety of effects. Ideally, the hope is that the damage occurs in a section of genes important to cell replication. This outcome stops the cancer from spreading any further.
Stronger Cancer
While radiation is still considered a viable treatment option for cancer, some research done indicates that cancer cells not affected by the radiation may actually become stronger. DukeHealth.org notes that when radiation is ineffective at treating cancer, the cancerous cells that survived the initial blast may become healthier when blood is diverted and brings more oxygen to the tumor. Tumors typically do not receive a lot of oxygen, and an increase in oxygen gives the cancerous cells a greater amount of energy for continuing cell processes.
