Men undergoing radiation therapy for prostate cancer who experience early side effects may face a significantly higher risk of developing severe long-term urinary and bowel complications, according to a new study led by UCLA Health Jonsson Comprehensive Cancer Center. The findings, which highlight the importance of managing acute side effects during treatment, could lead to better long-term outcomes and improved quality of life for patients.
The Impact of Acute Side Effects on Long-Term Health
Radiation therapy remains a critical treatment for localized prostate cancer, often delivering high doses to control the disease more effectively. However, while the treatment helps target the cancer, it can also cause damage to surrounding healthy tissues, resulting in both acute and late-term side effects. These side effects, particularly related to urinary and bowel functions, can severely affect a patient’s well-being, often for years after therapy ends.
The study, published in Lancet Oncology, found that men who experienced moderate acute urinary side effects in the first three months of radiation therapy were nearly twice as likely to develop severe long-term urinary complications, such as difficulty urinating or blood in the urine. Similarly, those who had early bowel-related side effects, such as softer stools or rectal discomfort, were nearly twice as likely to experience chronic bowel problems years after treatment.
The Significance of Acute and Late Toxicities
Acute toxicity refers to side effects that occur during radiation therapy or in the first three months following treatment. These typically resolve after the therapy concludes but can be distressing and significantly impact a patient’s quality of life. Common urinary acute side effects include increased frequency of urination, difficulty urinating, and discomfort during urination. Bowel issues, such as softer stools, diarrhea, and rectal discomfort, can also emerge in the acute phase.
In contrast, late toxicity refers to complications that arise months or even years after treatment. These effects can be long-lasting and can significantly affect day-to-day functioning. For example, late urinary toxicity includes narrowing of the urethra and hematuria (blood in the urine), while late bowel toxicities may involve rectal bleeding or the development of rectal ulcers. Late toxicities are particularly concerning as they tend to have a more significant and enduring impact on a person’s life compared to acute symptoms.
A Deeper Dive into the Connection Between Acute and Late Side Effects
The connection between acute and late side effects from radiation therapy has not been thoroughly explored until now. To gain a better understanding of this relationship, the UCLA research team analyzed data from over 6,500 prostate cancer patients who participated in six randomized phase 3 clinical trials. These trials provided detailed data on both short-term and long-term urinary and bowel side effects in patients who underwent radiation therapy.
The analysis revealed that patients who experienced moderate or worse acute urinary or bowel side effects were far more likely to develop severe late effects, even many years after treatment. Specifically, men who had early urinary problems had an increased rate of late urinary complications, from 7.5% to 12.5%, while men with acute bowel symptoms had an increased rate of late bowel issues, from 12.7% to 22.5%.
The Effect on Quality of Life
The study also highlighted that men who experienced early urinary or bowel side effects were more likely to report a significant decline in quality of life, including difficulty managing everyday activities. Men with moderate acute urinary toxicity were 1.4 times more likely to experience a clinically significant decline in urinary quality of life, while those with moderate acute bowel toxicity had a 1.5 times higher risk of experiencing a decline in bowel-related quality of life.
This data reinforces the idea that managing early side effects is crucial, not just for immediate relief but also for preventing long-term complications that can persist for years.
Potential Solutions: Innovations to Reduce Acute Toxicity
The findings of the study emphasize the importance of developing strategies to minimize acute side effects, as doing so could also reduce the likelihood of chronic complications. Dr. Amar Kishan, senior author of the study and executive vice chair of radiation oncology at the David Geffen School of Medicine at UCLA, stressed that advancements in radiation techniques could offer lasting benefits for patients.
“Innovative treatments like MRI-guided radiation and urethral-sparing techniques have the potential to reduce both acute and late side effects,” said Dr. Kishan. MRI-guided radiation therapy enables more precise targeting of the prostate tumor while sparing surrounding healthy tissues, which can help minimize both immediate and long-term side effects. Additionally, techniques such as urethral-sparing radiation, which places spacers between the prostate and surrounding tissues, can further protect healthy organs from radiation damage.
These newer methods could lead to better treatment outcomes by reducing radiation’s impact on healthy tissues and thereby lowering the risk of complications later on. However, as Dr. Kishan points out, more research is necessary to determine whether reducing acute side effects through these advanced techniques will also lead to improved long-term outcomes.
The Need for Further Research
While the study offers valuable insights into the link between early side effects and long-term complications, it also underscores the need for additional research. Future studies will be essential to understand whether early interventions to address acute side effects—such as medications or supportive therapies—can help prevent the development of more severe, lasting health issues.
“The findings of this study open up new opportunities for exploring how we can manage early side effects more effectively,” said Dr. John Nikitas, first author of the study and a resident in the Department of Radiation Oncology at UCLA Health. “If we can reduce acute toxicities, it could also improve the long-term quality of life for prostate cancer patients.”
Conclusion: A Step Toward Better Patient Care
As prostate cancer remains the most common cancer among men, and survival rates continue to improve, the goal of radiation therapy should not only be to effectively treat the cancer but also to enhance the overall quality of life for patients. The study from UCLA Health highlights the importance of recognizing the long-term risks associated with acute side effects and developing strategies to reduce these risks.
By focusing on innovations in radiation therapy and improving the management of early toxicities, healthcare providers can help men undergoing treatment for prostate cancer live longer, healthier lives. Reducing both acute and long-term side effects could ultimately improve patients’ quality of life and reduce the burden of chronic health issues caused by radiation therapy.
The full list of authors for the study includes Dr. Michael Steinberg, Dr. Luca Valle, Dr. Joanne Weidhaas, Parsa Jamshidian, Donatello Telesca, and Tahmineh Romero. The results of this research offer hope for better treatment options for men with prostate cancer, ultimately improving both their survival and quality of life.
Reference: John Nikitas et al, The interplay between acute and late toxicity among patients receiving prostate radiotherapy: an individual patient data meta-analysis of six randomised trials, The Lancet Oncology (2025). DOI: 10.1016/S1470-2045(24)00720-4