Early side effects of radiation can increase long-term risk for prostate cancer patients

Early side effects of radiation can increase long-term risk for prostate cancer patients

Those who undergo radiation therapy for prostate cancer early on may experience side effects, according to a new study led by researchers at the UCLA Health Jonsson Comprehensive Cancer Center.

The study found that patients who had moderate acute urinary side effects in the first three months after radiation were almost twice as likely to develop delayed urinary complications years later, compared to patients without early symptoms. Similarly, patients with early bowel side effects had nearly twice the risk of chronic bowel problems.

The results, published in theLancet OncologyHighlight the importance of developing strategies to better manage acute toxicities to improve long-term outcomes and quality of life for patients.

Men with prostate cancer are living longer than ever before, and our goal is to reduce the risk of late toxicities such as difficulty rectal bleeding, which can impact a patient's quality of life for years. This study highlights innovations we are developing, such as:

Dr. Amar Kishan, vice chair of radiation oncology at the David Geffen School of Medicine at UCLA and senior author of the study

Prostate cancer is the most common cancer in men, with radiation therapy often serving as a key treatment for localized prostate cancer and often involving higher doses to better control the disease. While this approach effectively controls cancer, it can also damage nearby healthy tissues and cause acute and late side effects.

Acute toxicity refers to side effects that occur during treatment or within the first three months after cessation, and they are typically temporary. Common urinary side effects include increased frequency of urination, difficulty urinating, and discomfort during urination. Bowel-related side effects may include looser stools or diarrhea, as well as rectal discomfort with bowel movements.

Late toxicity, on the other hand, can appear months or even years later and last for years. Late urinary toxicities include urethral narrowing and blood in the urine. Late intestinal toxicities include blood in the stool or an ulcer in the wall of the rectum. These problems can often have a greater impact on a person's quality of life compared to acute side effects.

While both acute and late toxicities are caused by the impact of radiation on healthy tissues, the relationship between the two has not been well studied, particularly using large data.

To better understand this relationship, researchers analyzed data from over 6,500 patients from six Phase 3 randomized clinical trials that included detailed individual-level data on short-term and long-term side effects affecting the urinary and intestinal systems.

The researchers found that patients with moderate or worse early side effects were more likely to experience serious late effects, even years after treatment. Men with previous problems or bowel problems were also more likely to report significant declines in their ability to manage daily activities and overall quality of life.

For urinary toxicity, acute toxicity increased the rate of late toxicity from 7.5% to 12.5% ​​and for intestinal toxicity with acute toxicity increased the rate of late toxicity from 12.7% to 22.5%.

The odds of having a clinically significant decline in urinary quality of life were 1.4 times higher for men who experienced moderate acute urinary toxicity. The odds of having a clinically significant decline in intestinal quality of life were 1.5 times higher for men who had moderate acute intestinal toxicity.

“These results demonstrate that acute toxicities following prostate radiotherapy are associated with late toxicities months and years later,” said Dr. John Nikitas, a resident in the Division of Radiation Oncology at UCLA Health and lead author of the study. “This highlights the importance of interventions that reduce the risk of acute toxicities, as they may also improve long-term outcomes and quality of life for patients.”

Kishan, who is also a researcher at the UCLA Health Jonsson Comprehensive Cancer Center, emphasized the potential impact of newer techniques to reduce both acute and late toxicities.

"Reducing early side effects through advanced techniques such as MRI-guided radiation, which allows more precise targeting of tumors, and urethral par methods, which use spacers between the prostate to protect surrounding tissues and rectum, may potentially lower the risk of budding side effects," Kishan said.

However, further studies are needed to determine whether specific strategies to reduce early side effects improve long-term outcomes and whether early treatment of short-term side effects can prevent long-term complications.

Other UCLA authors include Dr. Michael Steinberg, Dr. Luca Valle, Dr. Joanne Weidhaas, Parsa Jamshidian, Donatello Telesca and Tahmineh Romero. A full list of authors is included in the article.

The study was supported in part by grants from the National Institutes of Health and the Department of Defense.

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