• Posted April 16, 2025

Gene Test Predicts Urinary Problems From Prostate Cancer Radiation Therapy

Radiation therapy is commonly used to treat prostate cancer, but it can cause embarrassing urinary problems in some men.

But a new genetic test appears capable of sussing out which men are at greater risk of urinary side effects from radiation treatment, a new study says.

The test, PROSTOX, successfully predicted which men would eventually develop urinary problems following radiation cancer treatment, researchers reported in the journal Clinical Cancer Research.

“We’ve always known that some men develop these life-altering side effects that they will carry through the remainder of their lives, but until now, we didn’t have a way to predict who,” said senior researcher Dr. Joanne Weidhaas, vice chair of molecular and cellular oncology at the David Geffen School of Medicine at UCLA.

“What makes PROSTOX different is that it looks at a patient’s unique genetics to estimate their personal risk of developing side effects from radiation,” she said in a news release. “This helps doctors and patients choose the safest treatment and avoid unnecessary toxicities.”

Radiation used to treat the prostate can irritate the bladder, causing urinary incontinence, a need to urinate frequently or pain during urination, according to the American Cancer Society. The risk is initially low following treatment, but it goes up each year for several years.

In earlier studies, Weidhass and her team discovered that certain inherited genetic differences can predict the likelihood of these side effects.

Based on that, they developed PROSTOX, which evaluates 32 unique genetic factors related to radiation side effects. Early testing found that men found by the test to be at high risk were about 10 to 12 times more likely to develop urinary side effects.

For the new study, researchers set out to confirm that PROSTOX works in a new group of 148 patients who’d received stereotactic body radiotherapy (SBRT) for their prostate cancer. SBRT is a highly precise form of radiation therapy delivered over just five sessions.

Results showed that the test could predict which men would develop urinary side effects in the months and years following radiation treatment.

The study also found different genetic signatures between urinary side effects that would develop late but eventually fade, and side effects that would start early and never go away.

That means these two types of side effects likely occur for different reasons, researchers said.

Late-coming urinary symptoms appear to be connected to immune system problems and long-term inflammation, while persistent side effects seem to be caused by the type of radiation technology used in treatment, researchers said.

“This genre of genetic testing combined with advanced radiation therapy techniques will help personalize treatment for prostate cancer patients, mitigate the risk of serious genitourinary side effects, as well as give doctors and patients important information to make the best and safest treatment choices,” researcher Dr. Michael Steinberg said in a news releae. He's chair of radiation oncology at the David Geffen School of Medicine at UCLA.

Researchers plan to continue validating PROSTOX in larger patient populations, and are looking into similar genetic tests to predict side effects in other cancers following treatment.

“With further research, we hope to apply these genetic insights across cancer care,” Weidhaas said. “Ultimately, we want patients to survive cancer and live well after treatment.”

More information

The American Cancer Society has more on radiation therapy for prostate cancer.

SOURCE: UCLA, news release, April 7, 2024