I need external beam radiation for prostate cancer, will it have any bad effects on the rest of me?

not too bad. The majority of men do very well with radiation. During treatment there can be some fatigue, urinary changes and possibly some loose stools. Late term there can be a risk for erectile dysfunction, small risk for long term urinary changes, and especially with newer radiation techniques a small chance of rectal bleeding (proctitis).
Outcomes for. Prostate cancer compare quite favorably with surgery: they now have robots; we now have techniques that limit doses to healthy tissues. Proctitis rate is about 3%. Some depends on target, dose, genetic issues. Fatigue is in 1/3; no longer does any one get loose bowels. Erectile dysfunction depends on what you bring: we do not restore magic to wands that do not work. Age, smoking, dm, lipids add.
Radiation proctitis. I can only tell you what i see as a gastroenterologist. Radiation can cause inflammatory changes in the lining of the rectum called radiation proctitis. It can be treated by a gastroenterologist with argon gas therapy if it occurs. Good luck.

Related Questions

I need external beam radiation for prostate cancer will it cause fatigue?

Yes. Yes; but it is fairly mild. Most patients can continue their normal activities, including most jobs, except heavy manual labor. You may feel like taking a nap, or getting more sleep at night than you are used to. This gradually resolves by about 2-3 wks after radiation. Read more...
Fatigue may occur. Yes, fatigue is a common side effect. It varies quite a bit patient to patient, but generally is a mild symptom, and most people are able to carry out their usual routine during their course. Read more...
Yes. Many patients experience fatigue towards the end of their treatment. However, most individuals who work can continue to do so. Read more...