Stereotactic body radiation therapy reduces length of prostate cancer treatment

Sep 20 2007

Breihan Bridgewater suffers from emphysema. He sleeps on his side because when he lays flat on his back it feels like there's a boulder resting on his chest.

When the 74-year-old semi-retired electronic technician was diagnosed with prostate cancer, the thought of undergoing surgery or having to lie on his back and undergo more than 40 radiation treatments left him with an uneasy feeling – and a decision to make.

The Lewisville resident decided he would not seek treatment for his early-stage prostate cancer.

After Mr. Bridgewater told his UT Southwestern Medical Center doctors that the decision was determined because he didn't believe he could withstand the standard treatment for prostate cancer, they referred him to Dr. Robert Timmerman, vice chairman of radiation oncology.

Dr. Timmerman is leading a national clinical trial testing the effectiveness of stereotactic body radiation therapy (SBRT) to treat prostate cancer in five, 30-minute sessions.

The SBRT technique is a relatively new procedure used for treating localized tumors by delivering very high doses of focused radiation. Dr. Timmerman has successfully used the technique to treat patients with lung and liver cancers.

“There are a number of good treatments for prostate cancer, but they all have some drawbacks – they're inconvenient; they're invasive; or they cause impotence, rectal injury or urinary incontinence,” said Dr. Timmerman.

The three standard treatment options for early stage prostate cancer are:

• Prostatectomy, the surgical removal of the prostate gland, which can be done with minimally invasive techniques and robotic assistance;
• Brachytherapy, in which doctors implant numerous small radioactive seeds about the size of a grain of rice into the prostate gland using multiple large needles inserted through the skin. Once implanted, the seeds release their radioactivity directly into the prostate gland; and
• External beam radiation, which involves 42 to 45 treatments administered over two or more months, five days a week.

“This new treatment mimics the dose deposition of brachytherapy, but it is done noninvasively, in an outpatient setting, without making any incisions, needle punctures or anesthesia,” Dr. Timmerman said. “The beauty of it is that the patient only has to come in for five outpatient treatments and is finished in a week and a half.”

Dr. Timmerman has treated 11 patients at UT Southwestern using this new method with only minor side effects. As part of the study, he is trying to establish the treatment's proper dose protocol. He also is establishing study sites at the University of Minnesota, University of Colorado and at a rural practice in South Dakota.

Health-care experts predict that about 218,000 new cases of prostate cancer will be diagnosed in the U.S. this year, and more than 27,000 men will die from the disease.

Dr. Timmerman said the SBRT treatment might be ideal for people who live far away from an academic medical center or who can't stay away from their jobs for extended periods of time to receive treatment or recover.

“We're targeting this population because they clearly need a better treatment,” Dr. Timmerman said. “If the treatment ends up being favorable in its toxicity and side effects, then even ‘city slickers' might want to have it too.”

For Mr. Bridgewater, “the treatment was a breeze. I didn't have to do anything except breathe.”

And his prognosis is excellent. Tests show that the level of prostate-specific antigen (PSA) in Mr. Bridgewater's blood, which is elevated in men who have prostate cancer, was nearly nonexistent.

“Actually, we are seeing that the PSA levels in patients undergoing this new therapy are declining more rapidly than one would expect with conventional treatment,” Dr. Timmerman said. “It's still early in the study process, but it looks promising.”

Participants are still being recruited for the study. To qualify, patients must have early stage prostate cancer and a Gleason score of 7 or below. For more information contact Alida Perkins at 214-645-7633.

September is Prostate Cancer Awareness Month.