External Radiation for Prostate Cancer Radiation beams delivered from outside the patient are intended to penetrate the body and reach the prostate, thereby destroying the prostate cancer. The goal of external radiation is to deliver the maximum dose to the prostate, while reducing exposure of healthy nearby tissue (bowel, bladder and rectum). “Conformal Radiation” means delivering radiation beams in such a way as to conform to the shape of the patient’s prostate, thereby reducing the radiation given to the surrounding tissues. Different types of external radiation modalities have been created to deliver the most conformal beams possible. These include:            Helical Tomotherapy            IMRT (Intensity Modulated Radiation Therapy)            Proton Beam Radiation Therapy            3-Dimensional Conformal Beam Radiation Therapy Advantages of External Radiation:   With this modality, pain associated with surgery is avoided.  No anesthesia or invasive procedures are required.  In general a patient may continue with normal daily activities and work. Risks and disadvantages of External Radiation:   With this modality, some patients are required to have hormone therapy in conjunction.  Some patients do not want hormone therapy, due to it sexual side effects of impotence and reduced sexual drive.  Some patients feel inconvenienced since radiation is given over a six to eight week period, requiring daily visits (other than weekends) to the radiation facility.   It usually takes up to two years after radiation for the patient to know if he is cancer free.  Success of radiation depends on how low the PSA reaches after treatment, and PSA may not reach its lowest point for two years after radiation.   This protracted time period may cause anxiety in a patient’s mind, not knowing if he is clear of cancer or not.       Although uncommon, some patients may experience painful urination, burning sensation during urination, frequency and urgency of urination.  Other may experience bleeding from the bladder and incontinence, loss of urinary control.   Some patients may develop impotency (inability or decrease ability to have erections).  Some patients may experience increased bowel movements per day, burning with passing stool, or blood in the stool.