A five-year study shows that Stereotactic Body Radiation Therapy (SBRT) to treat prostate cancer offers a higher cure rate than more traditional approaches.
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.
Conventional treatment options for early stage prostate cancer include:
- 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 in the operating room. 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.
“The current form of radiation is 44 treatments given over nine weeks.”
“In contrast, the SBRT therapy we used to allow 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.
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. The findings are published in the European Journal of Cancer.
Terry Martin of McKinney, Texas, 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.”
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.
Citation: Hannan R, et al. (2016). Stereotactic body radiation therapy for low and intermediate risk prostate cancer—Results from a multi-institutional clinical trial. European Journal of Cancer, 59: 142. DOI: 10.1016/j.ejca.2016.02.014.
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