Prostate cancer: shorter radiation therapy is now a standard option

An updated guideline, built on strong evidence

On 27 October 2026, the American Society for Radiation Oncology (ASTRO) published an update of its guideline on radiation therapy for localized prostate cancer. It appears in the journal Practical Radiation Oncology and replaces the 2018 guideline, which had become too cautious in light of new data.

It was developed with the American Society of Clinical Oncology (ASCO), the American Urological Association (AUA), the European Society for Radiotherapy and Oncology (ESTRO) and the Society of Urologic Oncology (SUO), and it is endorsed by the AUA, ESTRO and SUO. For moderately hypofractionated radiation, it rests on randomized trials involving more than 7,000 patients, with long-term follow-up.

Two shorter formats, depending on the patient

Hypofractionated radiation delivers a slightly higher dose at each session, which reduces the number of sessions without changing the overall effect of treatment. Moderate hypofractionation is usually delivered over 4 to 6 weeks, with schedules of 6,000 to 6,200 cGy in 20 fractions or 7,000 cGy in 28 fractions.

Ultrahypofractionation, most often delivered as stereotactic body radiation therapy (SBRT), is concentrated into 5 sessions over one to two weeks, at a dose of 3,625 to 4,000 cGy in 5 fractions. Schedules of fewer than 5 fractions, however, are not recommended outside a clinical trial.

Who are these shorter treatments recommended for?

Moderately hypofractionated radiation is recommended over conventional radiation for all risk groups, for patients who choose external beam radiation therapy of the prostate, with or without the seminal vesicles, regardless of age, other illnesses, anatomy or baseline urinary function.

Five-session radiation becomes a standard option for low-risk patients who decline active surveillance and choose radiation, and for intermediate-risk patients. For high-risk or very high-risk cancers, it is conditionally recommended, meaning it is an option to discuss case by case.

Two nuances matter: for patients who already have significant urinary symptoms, moderate hypofractionation is preferred over the 5-session format, because larger doses per session may worsen urinary side effects. And treating the pelvic lymph nodes in 5 sessions is only envisaged within a clinical trial.

Why this changes patients' lives

A shorter course means fewer trips, less time off work and less fatigue from organizing care, with no loss of effectiveness. The guideline also stresses that access to these shorter treatments should be equitable, as their use still varies with age, treatment setting and social situation.

Treatment precision is part of the guideline: MRI-informed planning when appropriate, daily management of prostate motion and intensity-modulated radiation therapy. The choice of a rectal spacer, a device that moves the rectum away from the prostate, is also discussed with the patient.

Finally, whether or not to add hormone therapy is decided independently of the number of sessions: it depends on the risk of the cancer, not on the chosen radiation schedule.

What does not change

This guideline concerns localized prostate cancer treated with external beam radiation therapy. It decides nothing on its own: surgery, active surveillance and radiation therapy remain options whose choice depends on the cancer, symptoms, other illnesses and the patient's priorities, through shared decision-making with their doctors.

If you are affected by localized prostate cancer, do not hesitate to ask whether a shorter schedule could be considered in your case, at which center, and what urinary follow-up would be planned.

This article is for information only; it does not replace your doctor's advice.