Radiotherapy for Prostate Cancer

Radiation therapy works by generating free radicals that result in DNA damage, cell death, and tumor regression. Waves that are produced during therapeutic radiotherapy, most often X-ray or gamma-ray photons, act as sources of energy that disrupt orbital electrons to cause the formation of free radicals, which lead to damage to the cells (Jameson et al., Principles of cancer treatment. In: Harrison’s principles of internal medicine. 20th ed. New York: McGraw-Hill, 2018. Available from http://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192014984). The dose of radiation therapy, or gray (Gy), is the amount of measured radiation that is absorbed by the tissues of the body (Jameson et al., Principles of cancer treatment. In: Harrison’s principles of internal medicine. 20th ed. New York: McGraw-Hill, 2018. Available from http://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192014984). Cells that are not in the process of division when the radiotherapy is delivered are not as vulnerable to the effect of the radiation (Jameson et al., Principles of cancer treatment. In: Harrison’s principles of internal medicine. 20th ed. New York: McGraw-Hill, 2018. Available from http://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192014984). Therefore, giving smaller doses of radiotherapy over periods of time allows for more cells to be exposed to the effects of the radiation and also allows for recovery of normal tissues around the area of the tumor (Jameson et al., Principles of cancer treatment. In: Harrison’s principles of internal medicine. 20th ed. New York: McGraw-Hill, 2018. Available from http://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192014984).