ASTRO updates guideline on shorter-course radiation therapy for localized prostate cancer

An updated clinical guideline from the American Society for Radiation Oncology (ASTRO) provides evidence-based recommendations on the use of hypofractionated radiation therapy for patients with localized prostate cancer. The guideline replaces ASTRO’s 2018 recommendations and reflects a substantially matured evidence base showing that shorter-course radiation therapy can maintain cancer control while reducing overall treatment burden for patients receiving definitive external beam radiation therapy (EBRT). The guideline was published in Practical Radiation Oncology, ASTRO’s clinical practice journal.

Approximately one in eight men will be diagnosed with prostate cancer during their lifetime. It is the second most common cancer among men in the United States, after skin cancer. In 2026, nearly 334,000 new cases of prostate cancer will be diagnosed among U.S. adults. When prostate cancer is diagnosed while still localized, outcomes are generally excellent, and patients often have several effective approaches to consider based on their individual priorities.

For patients with localized prostate cancer who choose radiation therapy, EBRT is a standard definitive treatment option. Hypofractionated EBRT delivers radiation therapy in fewer treatment sessions than conventional fractionation, using a higher dose per treatment while maintaining a similar overall therapeutic effect. Moderate hypofractionation typically is delivered over four to six weeks, while ultrahypofractionation, most commonly delivered as stereotactic body radiation therapy (SBRT), allows patients to complete treatment in five sessions over one to two weeks.

The updated guideline recommends moderate hypofractionation over conventional fractionation for patients across all prostate cancer risk groups who choose EBRT, supported by high-quality randomized data showing comparable outcomes, side effects and quality of life. It also strongly recommends ultrahypofractionation as a standard option for many patients, including those with intermediate-risk disease, marking a broader role for five-treatment SBRT in prostate cancer care.

“SBRT has moved from a promising alternative to a standard treatment option for many patients with localized prostate cancer,” said guideline task force chair Scott C. Morgan, MD, a radiation oncologist at The Ottawa Hospital and professor of radiation oncology at the University of Ottawa. “These recommendations give clinicians clear direction on using shorter-course treatment safely while preserving the excellent outcomes patients expect from definitive radiation therapy.”

“The evidence supporting hypofractionation is now much stronger in the years since ASTRO’s previous guideline was published,” said guideline task force vice chair Karen Hoffman, MD, MPH, FASTRO, a professor of radiation oncology and the Mays Radiation Oncology Center Medical Director at The University of Texas MD Anderson Cancer Center. “This guideline also reflects how treatment planning has evolved, including greater use of daily image guidance and more precise approaches to managing motion during treatment.”

Key recommendations from the guideline are listed below. Shared decision making between physicians and patients is emphasized throughout, particularly when treatment options vary by risk group, baseline urinary function and patient preferences.

Indications for Moderate Hypofractionation

• For patients with localized prostate cancer receiving EBRT to the prostate with or without treatment of the seminal vesicles, moderate hypofractionation is recommended over conventional fractionation across all risk groups. The guideline notes that randomized trials involving more than 7,000 patients support this approach, with long-term data showing comparable cancer control, side effect profiles and quality of life.

• Moderate hypofractionation is recommended regardless of patient age, comorbidity, anatomy or baseline urinary function. The guideline also states that decisions about androgen deprivation therapy should be made independently from the choice of fractionation regimen.

• For patients receiving elective pelvic nodal radiation therapy, moderate hypofractionation to the prostate with concurrent conventional or near-conventional radiation therapy to the pelvic lymph nodes is recommended using a single-phase plan.

Indications for Ultrahypofractionation

• Ultrahypofractionated EBRT is recommended as a treatment option for patients with low-risk localized prostate cancer who decline active surveillance and choose EBRT, as well as for patients with intermediate-risk disease receiving EBRT to the prostate and seminal vesicles. For patients with high-risk or very high-risk disease, ultrahypofractionated EBRT is conditionally recommended as a treatment option.

• For patients with significant baseline urinary symptoms, moderate hypofractionation is conditionally recommended over ultrahypofractionation. The guideline notes that ultrahypofractionation may increase the risk of treatment-related urinary side effects for patients with substantial preexisting lower urinary tract symptoms.

• Ultrahypofractionated EBRT for elective pelvic nodal treatment is conditionally recommended only as part of a clinical trial.

Dose, Target Volumes and Treatment Delivery

• For moderately hypofractionated EBRT, recommended dose schedules include 6000-6200 cGy in 20 fractions or 7000 cGy in 28 fractions. For ultrahypofractionated EBRT, a dose of 3625-4000 cGy in five fractions is conditionally recommended, while regimens using fewer than five fractions are not recommended outside of a clinical trial.

• Recommendations for target volumes vary by risk group and disease features. For patients with low-risk disease declining an active surveillance approach, treatment of the prostate alone is recommended. For patients with higher-risk disease, inclusion of at least part of the seminal vesicles is recommended or conditionally recommended depending on clinical risk, and focal intraprostatic boost may be considered for selected patients with a dominant lesion visible on MRI.

• Best practices for treatment planning and delivery emphasize precision and safety, including MRI-informed planning when appropriate, daily motion management and intensity modulated radiation therapy. The guideline also conditionally recommends intrafraction tracking for patients receiving ultrahypofractionated EBRT and discusses use of rectal spacers as part of shared decision making.

The guideline also highlights important implementation and equity considerations. In national datasets, use of hypofractionated EBRT has varied by age, race, socioeconomic factors and treatment setting. Because shorter-course treatment can reduce travel, time away from work and other burdens associated with care, the guideline notes that equitable access to high-quality hypofractionated radiation therapy should remain a priority.

About the Guideline

“Hypofractionated Radiation Therapy for Localized Prostate Cancer: An ASTRO Clinical Practice Guideline” was developed by a multidisciplinary task force of radiation, medical and urological oncologists, as well as a medical physicist and patient representative. The guideline was developed in collaboration with the American Society of Clinical Oncology, the American Urological Association (AUA), the European Society for Radiotherapy and Oncology (ESTRO) and the Society of Urologic Oncology (SUO). It was endorsed by AUA, ESTRO and SUO.

The recommendations are based on a systematic evidence review funded by the Patient-Centered Outcomes Research Institute and conducted by the Agency for Healthcare Research and Quality, supplemented by ASTRO’s formal guideline development process and expert consensus where evidence was limited.

ASTRO’s clinical guidelines are intended as tools to promote appropriately individualized, shared decision-making between physicians and patients. None should be construed as strict or superseding the appropriately informed and considered judgments of individual physicians and patients.

ABOUT ASTRO

The American Society for Radiation Oncology (ASTRO) is the world’s largest professional society dedicated to advancing radiation medicine, with 11,000 members including physicians, nurses, physicists, radiation therapists, dosimetrists and other professionals who work to improve patient outcomes through clinical care, research, education and advocacy. Radiation therapy is integral to 40% of cancer cures worldwide, and more than one million Americans receive radiation treatments for their cancer each year. For information on radiation therapy, visit Speed of Light – The ASTRO Foundation. To learn more about ASTRO, visit our website and press room and connect with us on social media.