Higher doses of radiation in fewer treatments proved safe, effective for low-risk prostate cancer

June 2, 2011, UT Southwestern Medical Center

In a multicenter clinical trial, UT Southwestern Medical Center researchers have found that higher doses of stereotactic radiation therapy requiring fewer treatments are safe and effective for patients with low-to-intermediate-risk prostate cancer.

Results of the trial, available in the , showed that stereotactic body (SBRT), which delivers ultra-precise radiation, was effective in treating patients with localized in five 30-minute sessions every other day over two weeks. That compares to the typical radiation protocol for prostate cancer of 42 to 45 daily treatments administered over eight to nine weeks.

"We were trying to develop a fast, convenient, outpatient, non-invasive treatment," said Dr. Robert Timmerman, vice chairman of and professor of and senior author of the study. "In the low-risk population, there are a lot of good options, but none of them are altogether convenient. The most convenient treatment would finish quickly without the need for a prolonged recovery."

SBRT has been used in the last decade to treat patients with lung, liver and brain cancers. The current study tested whether high-potency treatments would work in a like the prostate, which moves considerably due to normal bladder and bowel filling.

"We're trying to kill the prostate cancer, but without injuring the urethra, the bladder or the rectum," Dr. Timmerman said. "Each treatment had to be very potent in order to get the full radiation effect in only five treatments."

To avoid injury to healthy tissue, researchers used beams of radiation that were just millimeters larger than the target itself. That narrow scope helped avoid consequences such as rectal injury, impotence and difficulty urinating.

Prostate cancer is the most common cancer in men, with some 200,000 diagnosed each year in the U.S. About half of those who are treated undergo radiation therapy, typically for eight weeks. Not everyone is cured, however, because some tumors are resistant to radiation.

In the current clinical trial, researchers tested escalating doses for safety levels in 45 patients enrolled from November 2006 to May 2009. In a 90-day follow-up procedure, they looked at how much injury occurred in adjacent areas, including the rectum or urethra, and any changes to the patients' quality of life.

"There were a few more complications associated with higher doses, but they were fairly predictable and rarely severe," said Dr. Yair Lotan, associate professor of urology and a co-author of the study. "By giving these higher doses, we might be able to kill more resistant tumors with shorter treatments."

In the next stage of the clinical trial, a larger group of patients will be treated at one dosage level, and follow-up will be 18 months.

Explore further: Tissue spacers reduce risk of rectal injury for prostate cancer patients

Related Stories

Tissue spacers reduce risk of rectal injury for prostate cancer patients

April 29, 2011
Injecting a tissue spacer in the prostate-rectal inter-space is an effective way to reduce the rectal dose for prostate cancer patients receiving radiation therapy, according to research presented April 30, 2011, at the Cancer ...

Recommended for you

Researchers find pathways that uncover insight into development of lung cancer

August 17, 2018
Lung cancer is the leading cause of preventable cancer death. A disease of complex origin, lung cancer is usually considered to result from effects of smoking and from multiple genetic variants. One of these genetic components, ...

Developing an on-off switch for breast cancer treatment

August 17, 2018
T-cells play an important role in the body's immune system, and one of their tasks is to find and destroy infection. However, T-cells struggle to identify solid, cancerous tumors in the body. A current cancer therapy is using ...

Scientists discover new method of diagnosing cancer with malaria protein

August 17, 2018
In a spectacular new study, researchers from the University of Copenhagen have discovered a method of diagnosing a broad range of cancers at their early stages by utilising a particular malaria protein that sticks to cancer ...

Pregnant? Eating broccoli sprouts may reduce child's chances of breast cancer later in life

August 16, 2018
Researchers at the University of Alabama at Birmingham have found that a plant-based diet is more effective in preventing breast cancer later in life for the child if the mother consumed broccoli while pregnant. The 2018 ...

Three scientists share $500,000 prize for work on cancer therapy

August 15, 2018
Tumors once considered untreatable have disappeared and people previously given months to live are surviving for decades thanks to new therapies emerging from the work of three scientists chosen to receive a $500,000 medical ...

PARP inhibitor improves progression-free survival in patients with advanced breast cancers

August 15, 2018
In a randomized, Phase III trial led by researchers at The University of Texas MD Anderson Cancer Center, the PARP inhibitor talazoparib extended progression-free survival (PFS) and improved quality-of-life measures over ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.