Updated ASTRO Guidelines Expand Role of Hypofractionated Radiotherapy in Localized Prostate Cancer

Clinical Summary: 

• Guideline Update: The American Society for Radiation Oncology (ASTRO) updated its clinical practice guidelines for hypofractionated external beam radiation therapy (EBRT) in localized prostate cancer, recommending moderate hypofractionation over conventional fractionation across all risk groups and expanding the role of ultrahypofractionation.

• Key Recommendations: Moderate hypofractionation is recommended across all risk groups, while ultrahypofractionation, commonly delivered as stereotactic body radiation therapy (SBRT), is recommended for selected patients with low- or intermediate-risk disease and conditionally recommended for high- or very high-risk disease.

• Clinical Relevance: These recommendations support broader use of shorter-course radiotherapy to reduce treatment burden while maintaining cancer control, emphasizing individualized treatment selection, baseline urinary function, and shared decision-making.

Updated American Society for Radiation Oncology (ASTRO) clinical practice guidelines recommend moderate hypofractionated radiotherapy over conventional fractionation across all localized prostate cancer risk groups and expand the role of ultrahypofractionation, including stereotactic body radiation therapy (SBRT), as a treatment option for selected patients.

The updated recommendations, published in Practical Radiation Oncology, replace ASTRO’s 2018 guidance and reflect growing evidence supporting shorter-course external beam radiation therapy (EBRT) while maintaining cancer control and reducing treatment burden.

The guideline recommends moderate hypofractionation over conventional fractionation for patients with localized prostate cancer receiving EBRT to the prostate, with or without treatment of the seminal vesicles, across all risk groups. The recommendation is supported by randomized trials involving more than 7000 patients, with long-term findings demonstrating comparable cancer control, adverse event profiles, and quality of life.

Moderate hypofractionation, typically administered over 4 to 6 weeks, is recommended regardless of patient age, comorbidities, anatomy, or baseline urinary function. Decisions regarding androgen deprivation therapy should be made independently of the selected fractionation regimen.

For patients receiving elective pelvic nodal radiotherapy, the guideline recommends moderate hypofractionation to the prostate with concurrent conventional or near-conventional radiotherapy to the pelvic lymph nodes using a single-phase treatment plan.

The updated guidance also expands the role of ultrahypofractionation, commonly delivered as SBRT in 5 treatment sessions over 1 to 2 weeks.

Ultrahypofractionated EBRT is recommended as a treatment option for patients with low-risk localized prostate cancer who decline active surveillance and elect radiation therapy, as well as patients with intermediate-risk disease receiving EBRT to the prostate and seminal vesicles.

For patients with high-risk or very high-risk localized prostate cancer, ultrahypofractionation is conditionally recommended as a treatment option. However, for patients with significant baseline urinary symptoms, moderate hypofractionation is conditionally recommended over ultrahypofractionation because of the potential for increased treatment-related urinary toxicity.

The guideline also conditionally recommends ultrahypofractionated EBRT for elective pelvic nodal treatment only within a clinical trial.

Recommended dose schedules for moderate hypofractionation include 6000 to 6200 cGy in 20 fractions or 7000 cGy in 28 fractions. For ultrahypofractionation, 3625 to 4000 cGy in 5 fractions is conditionally recommended, while regimens using fewer than 5 fractions are not recommended outside a clinical trial.

Target volume recommendations vary according to disease risk and clinical characteristics.

For patients with low-risk prostate cancer who decline active surveillance, 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.

Focal intraprostatic boost may also be considered for selected patients with a dominant lesion identified on magnetic resonance imaging (MRI).

The guideline emphasizes precision in treatment planning and delivery, including MRI-informed planning when appropriate, daily motion management, and intensity-modulated radiation therapy.

Intrafraction tracking is conditionally recommended for patients receiving ultrahypofractionated EBRT, while the use of rectal spacers should be considered through shared decision-making.

“The evidence supporting hypofractionation is now much stronger in the years since ASTRO’s previous guideline was published,” stated Karen Hoffman, MD, MPH, FASTRO, guideline task force vice chair and professor of radiation oncology at MD Anderson Cancer Center, Houston, Texas. 

The recommendations also address access to shorter-course radiotherapy, noting that treatment utilization varies according to age, race, socioeconomic factors, and treatment setting.

By reducing the number of treatment visits, hypofractionated radiotherapy may help lessen travel requirements, time away from work, and other burdens associated with cancer care.

The guideline emphasizes equitable access to high-quality hypofractionated radiotherapy and shared decision-making that accounts for individual disease characteristics, baseline urinary function, and patient preferences.

The updated recommendations support moderate hypofractionation as the preferred approach over conventional fractionation for patients with localized prostate cancer receiving EBRT, while establishing a broader role for ultrahypofractionation in appropriately selected patients.

Source: 

ASTRO. ASTRO updates guideline on shorter-course radiation therapy for localized prostate cancer. Accessed on: October 30, 2026. https://www.astro.org/news-and-publications/news-and-media-center/news-releases/2026/astro-updates-guideline-on-shorter-course-radiation-therapy-for-localized-prostate-cancer