Zapping Prostate Cancer With Radiation: How Does It Work?

ByABC News
February 22, 2006, 4:45 PM

Feb. 22, 2006 — -- Choosing a treatment for prostate cancer can be mind-boggling. Not only are there different types of prostate cancer -- some more severe than others -- but also many different treatment options, from radiation to surgery to watchful waiting.

If a man decides on radiation to treat his early-stage prostate cancer, he has two basic choices: external-beam radiation or radioactive-seed implantation. Both seem equally effective.

Prostate cancer patient Bob Booth recently began a series of external-beam radiation treatments, also known as intensity-modulated radiation therapy, or IMRT. It delivers a high dose of radiation to just the right areas through a focused beam.

"We literally have the ability to sculpt radiation around different structures and say, 'This area we want to get full-dose radiation, and we want to protect these adjacent structures,'" said Dr. Eric Horwitz, an associate professor and director of the radiation oncology training program at the Fox Chase Cancer Center in Philadelphia.

What makes IMRT advanced is the preplanning. First, the prostate, bladder and rectum are located through magnetic resonance imaging, or MRI. The information is then loaded into a computer.

"We're making sure his prostate gets 100 percent of the radiation," Horwitz said, "but we're really able to limit the radiation both to his rectum and his bladder."

"Each day they're going to retarget my prostate, so it's a very focused radiation treatment over a period of time," explained Booth.

But IMRT isn't for everyone, as it's a five-day-a-week treatment that lasts seven to eight weeks.

The other option, radioactive-seed implantation, is typically used for men with lower-grade tumors, and yields good results, doctors say.

About 50 seeds are usually implanted, guided by a computer.

"It's a one-day procedure, a couple of hours at the most and you're over and done," said Dr. Ronald Ennis, of the department of radiation oncology at St. Luke's - Roosevelt Hospital in New York.