Radiation therapy is a form of local therapy used to treat many different types of cancer. Radiation therapy uses high energy X-rays (photons) or particles from atoms (electrons) to treat tumors. The radiation used cannot be seen, or felt, and is not radioactive. The radiation will pass through the body in the designated region needing treatment. Radiation creates DNA damage in both normal and tumor cells, and when they try to undergo cellular division the cells die if they were unable to repair the DNA damage created. The damage created in the cells can lead to cell death within hours to weeks after a treatment is given.
For each radiation treatment, patients will need to be placed under general anesthesia as they must remain perfectly still for correct and repeatable tumor targeting. The duration of anesthesia for each treatment is typically only a few minutes and most patients are fully treated and recovered within 1 to 2 hours.
There are two types of radiation protocols used: Definitive intent or palliative intent. The recommendations for which protocol to use will vary based on tumor type, location, and stage of disease. The protocols are often combined with surgery and/or chemotherapy. Definitive intent radiation is given with a goal of trying to deliver as much radiation as safely as possible to achieve a maximum dose into the tumor as to control the tumor for as long as possible. Definitive intent protocols are given in a series of 10-20 daily treatments over 2-4 weeks. Palliative intent radiation is given with a goal of trying to improve quality of life of a patient. Palliative intent protocols are typically given as 4 to 6 weekly treatments.
Radiation therapy does cause side effects depending on the location of the tumor, the protocol used and the goal of treatment. In general, side effects are limited to the region being treated with radiation and can range from minimal to severe but most of the side effects are considered temporary.