Narrator: When the cancer is not completely contained in the prostate or when the patient is older the treatment that is frequently used is radiation therapy.

Gunnar Zagars, M.D.: There are different forms of radiation for prostate cancer. They really boil down to two different types. There's what we call external beam treatment, which is given from an x-ray machine, and there's a variety called interstitial implantation, which uses radioactive seeds. Both of those treatments use radioactive sources, the difference being that in the external beam the treatment comes from outside the patient, whereas with the interstitial seed treatment the radioactive sources are inserted into the prostate.

[ beeping ]

Narrator: The more common form of radiation therapy is external beam. A typical treatment takes seven weeks.

Gunnar Zagars, M.D.: A patient comes in every day, Monday to Friday. Each treatment itself is probably pretty quick -- you're probably looking at five minutes.

Technician: Hi, Mr. Fabec, how ya doing?

Al Fabec: Fine.

Technician: Good, you ready?

Al Fabec: Oh, yes.

Gunnar Zagars, M.D.: The patient doesn't feel anything during the treatment. You can't really feel the x-rays going into you and so they feel no different after the treatment than before.

Al Fabec: They put the beam above you and put the light on it and when it's perfectly set up on these markings on your body you're ready to go.

Technician: Okay, Mr. Fabec, here we go.

[ beeping ]

Al Fabec: You keep your hands like this and lay on the table. Count like, "One, two, three," up to 15. So, just about that and you’re finished.

Technician: Okay, buddy.

Al Fabec: Alright.

Technician: Thank you.

Gunnar Zagars, M.D.: A few side affects do occur as you get into the treatment. Typically these patients when they get into the second or third week have some irritation of their bladder so they end up going to the bathroom more often. They can have some irritation of the rectum -- it feels like hemorrhoidal problems. These are usually pretty minor and we've got some good medication and they tend to disappear usually about two to four weeks after we're finished.

Narrator: But while radiation is considered effective, it doesn't kill all the cancer in about half the patients who receive it and there's no way to predict when or even if the remaining cancer cells will become active again.

Christopher Wood, M.D.: It's at the ten-year mark where the differences between success rates with radical prostatectomy and radiation therapy become evident, and if you're not going to live ten years then I'm not sure that it's worthwhile to put you through a major operation like radical prostatectomy, and in those situations, I do refer patients for radiation therapy -- either external beam or brachytherapy.