A noninvasive form of radiation brings hope in prostate cancer

18 Apr 2016

A five-year study shows that Stereotactic Body Radiation Therapy (SBRT) to treat prostate cancer offers a higher cure rate than more traditional approaches, according to researchers at UT Southwestern Medical Center Harold C. Simmons Comprehensive Cancer Center.

The study -- the first trial to publish five-year results from SBRT treatment for prostate cancer -- found a 98.6% cure rate with SBRT, a noninvasive form of radiation treatment that involves high-dose radiation beams entering the body through various angles and intersecting at the desired target. It is a state-of-the-art technology that allows for a concentrated dose to reach the tumor while limiting the radiation dose to surrounding healthy tissue.

Is there any difference between the current form of radiation and SBRT therapy?

"The high cure rate is striking when compared to the reported five-year cure rates from other approaches like surgery or conventional radiation, which range between 80 to 90%, while the side effects of this treatment are comparable to other types of treatment," said Dr. Raquibul Hannan, Assistant Professor of Radiation Oncology and lead author for the study. "What we now have is a more potent and effective form of completely noninvasive treatment for prostate cancer, conveniently completed in five treatments."

"The current form of radiation is 44 treatments given over nine weeks. In contrast, the SBRT therapy we used allows the delivery of highly focused radiation in only five treatments, allowing patients to return to their normal lives more quickly," said senior author Dr. Robert Timmerman, Director of the Annette Simmons Stereotactic Treatment Center at UT Southwestern, and Professor and Vice Chairman of the Department of Radiation Oncology. "SBRT is both more convenient and has increased potency."

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Shorter treatment times: a compelling advantage for the patient

UT Southwestern served as the lead site for the multi-institutional clinical trial, which involved first-time prostate cancer patients diagnosed with stage I or stage II (low and intermediate risk) prostate cancer. A total of 91 patients were treated prospectively and followed for five years, with only one patient experiencing a recurrence of his cancer.

Terry Martin of McKinney, Texas, -- about an hour outside Dallas -- said the fewer number of treatments was a compelling advantage when he was evaluating treatment options.

"I live 45 minutes away from UT Southwestern. The difference between being treated five times versus 44 times is enormous," said Mr. Martin, a retired airline pilot. "I felt that I was back to normal just 10 days after finishing treatment."

What about the side effects of the treatment?

In addition to shorter treatment times, researchers found that side effects were not necessarily different compared to other forms of prostate cancer treatment. In the short term, the side effects of SBRT can include urinary issues (urgency, frequency and burning) and rectal irritation, which are often temporary and reverse within four weeks of treatment. Researchers found a small risk of longer-term urinary and rectal complications, which is also comparable to conventional treatments. Decrease in erectile function was seen in 25% of patients, fewer than with conventional radiation or surgery, said Dr. Hannan.

To reduce the side effects associated with SBRT, current clinical trials at UTSW are using a unique and biodegradable rectal spacer gel to protect the rectum.

Other clinical trials at the UTSW Department of Radiation Oncology are seeking to expand the application of SBRT to high-risk (Stage III) prostate cancer patients. "Our hope is that the high potency of this form of treatment will significantly improve treatment of these patients," says Dr. Hannan, the principal investigator of the high-risk prostate SBRT trial.

Source: Science Daily
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