Shorter Prostate Cancer Radiotherapy – 7 Weeks Down to 5: Who It Suits and Who It Doesn’t

Twelve Fewer Hospital Trips: The Gains and Costs of Shorter Radiotherapy

Some men who have had surgery for prostate cancer need radiotherapy to the prostate bed, either because their risk of recurrence is high or because their PSA has started to rise again. The standard course lasts about 7 weeks, with 37 sessions. Five-year results of the NRG-GU003 trial, presented at ASTRO 2026 on September 27, showed that the same treatment can be delivered in about 5 weeks, in 25 sessions: cancer control and patient-reported quality of life were similar, but serious urinary side effects were more common. We have previously covered 5-session radiotherapy for patients who have not had surgery; this trial asks a similar question for the postoperative setting.

Why does this matter?

Prostate cancer is one of the most common cancers in men, and one of the most frequently used treatments for early-stage disease is radical prostatectomy, open or robotic surgery to remove the entire prostate. When postoperative pathology shows that the tumor has spread beyond the prostate or that the surgical margin is positive, or when PSA rises again during follow-up, radiotherapy is given to the area where the prostate used to be (the prostate bed). Surgery and radiotherapy are often complementary rather than alternatives. Given at the right time, this treatment controls the disease in a substantial proportion of patients.

However, traveling to the hospital every weekday for 7 weeks is a real burden, especially for patients who work, older patients and those coming from another city. In prostate cancer that has not been operated on, giving radiotherapy in fewer sessions with higher daily doses (hypofractionation) has been one of the standards for years; these advances have also shaped the surgery-versus-radiotherapy debate. After surgery, however, neighboring organs such as the bladder and rectum lie closer to the treatment field in the prostate bed, so this approach was viewed with more caution. NRG-GU003 is the largest randomized trial to address this question.

Can radiotherapy after prostate surgery be shortened to 5 weeks?

Yes, for suitable patients. In the NRG-GU003 phase 3 trial, 25-session, 5-week hypofractionated radiotherapy provided cancer control and quality of life at 5 years similar to those of the 37-session, 7-week standard course. However, serious radiation cystitis and hematuria were more common with the shorter course. For patients with pre-existing urinary problems, the standard course may be preferred.

How was NRG-GU003 conducted?

The trial enrolled patients who had high-risk features on postoperative pathology or whose PSA had started to rise again, and randomly assigned them to two groups. The primary objective was to show that patient-reported urinary and bowel symptoms 2 years after treatment were not worse with the shorter course than with conventional fractionation; this objective was met in the primary analysis published in 2024. In the update presented at ASTRO 2026, median follow-up reached 7 years.

Five-year results

Similar cancer control

At 5 years, biochemical recurrence, defined as PSA rising to 0.4 ng/mL or higher and continuing to rise, occurred in 18% of patients with conventional fractionation and 21% with the shorter course (p=0.3). Although this means about 3 more recurrences per 100 patients in absolute terms, the difference was not statistically significant. During the trial, 31 patients died (14 and 17); only 4 of these deaths were due to prostate cancer. This suggests that, in patients receiving postoperative radiotherapy, causes other than cancer play a larger role in survival.

Similar patient-reported quality of life

Negative values indicate worsening symptoms. The differences between the two groups were small and not significant. However, only 56% of patients completed the questionnaires at year 5; the possibility that non-responders had different symptoms limits this finding.

Serious urinary side effects were more common

Physician-assessed grade 3 side effects, meaning those that markedly affect daily life or require treatment, were significantly more common with the shorter course. Scores measuring patient-reported bowel symptoms (such as rectal bleeding and frequent bowel movements) did not differ significantly between the groups. The difference came mainly from the urinary tract: non-infective bladder inflammation (radiation cystitis) and hematuria. No patient had a grade 4 or 5 side effect, and the timing of side-effect onset did not differ between the groups.

One apparent contradiction stands out: while patient-reported urinary symptoms were similar in the two groups, physician-recorded serious urinary side effects were 4 times more common with the shorter course. Possible explanations include questionnaires not capturing every symptom, serious events being concentrated in a small number of patients, and low questionnaire completion. The authors note that these rates are consistent with contemporary series.

How should the results be interpreted?

Strengths

• The largest randomized phase 3 clinical trial comparing the number of sessions for postoperative radiotherapy.
• Long median follow-up of 7 years; both patient-reported and physician-reported outcomes were assessed together.
• A balanced and transparent picture of cancer control, quality of life and side effects: both the gains and the costs are clearly visible.

Points of caution

• Not designed for cancer control: The primary endpoint was quality of life. The trial was not large enough to rule out with certainty a real 3-point difference in biochemical recurrence.
• Low questionnaire completion: At year 5, only about half of patients completed the questionnaires.
• Limited scope: Only the prostate bed was irradiated; biological subtypes of the disease were not assessed; no separate results were reported for patients whose treatment field included the lymph nodes or for subgroups receiving hormone (testosterone-suppressing) therapy.
• Conference data: The 5-year results have not yet been published as a full peer-reviewed article.

Practical information for patients receiving radiotherapy after surgery

• Timing: Large randomized trials have shown that early "salvage" radiotherapy, started once PSA begins to rise, is as effective for most patients as radiotherapy given routinely right after surgery. This is why regular PSA monitoring after surgery is so important.
• Plan for the treatment period: Discussing in advance how treatment will affect your daily life makes it easier to prepare.
• Discuss the number of sessions: Talk with your radiation oncologist about the pros and cons of the 25-session and 37-session options. Travel difficulties, your work situation and any existing urinary symptoms are key factors in this decision.
• Bladder preparation: Having a similarly filled bladder at every session helps reduce the dose the bladder receives. Follow the drinking schedule recommended by your center.
• Report symptoms: Tell your care team about symptoms such as blood in the urine, burning, frequent urination or inability to urinate, even if they appear months or even years after treatment ends. Radiation cystitis can usually be treated. Bowel symptoms that may occur during radiotherapy, such as diarrhea, are also usually temporary.
• Sexual health and quality of life: Surgery and radiotherapy can affect sexual function; getting support in this area should be part of treatment, and exercise has also been shown to help. Radiotherapy-related fatigue is also usually temporary.

Frequently asked questions

How many sessions does radiotherapy after prostate surgery take?

The standard course is 37 sessions over about 7 weeks. The NRG-GU003 phase 3 trial showed that, for suitable patients, treatment can be shortened to 25 sessions over about 5 weeks. The choice is made together with the radiation oncologist, based on the patient's urinary symptoms and other characteristics.

Is shorter radiotherapy just as effective at controlling the cancer?

In the 5-year results, recurrence defined by a rising PSA occurred in 21% of patients with the shorter course and 18% with the standard course, and the difference was not significant. However, the trial was not designed to be large enough to detect small differences in cancer control with certainty.

Does shorter radiotherapy cause more side effects?

Patient-reported quality of life was similar. However, physician-recorded serious urinary side effects, particularly radiation cystitis and hematuria, were more common with the shorter course (13% vs. 3%). For patients with pre-existing urinary problems, the standard course may be preferred.

Does everyone need radiotherapy after surgery?

No. Radiotherapy is considered when pathology shows that the tumor has spread beyond the prostate, when the surgical margin is positive, or when PSA rises again during follow-up. For many patients, the preferred approach is regular PSA monitoring, with early radiotherapy if PSA rises.

Glossary

Radical prostatectomy

Surgical removal of the entire prostate along with some surrounding tissue.

Prostate bed

The area where the prostate was removed, which is the target of radiotherapy.

Hypofractionation

Delivering radiotherapy in fewer sessions, with a higher dose at each session.

Gray (Gy)

The unit of radiation dose delivered to the body in radiotherapy.

Biochemical recurrence

A rise in PSA above a set threshold after treatment that continues to rise; the first sign of recurrence, before disease can be detected on imaging.

Radiation cystitis

Bladder inflammation caused by radiation therapy; it can lead to frequent urination, burning and blood in the urine.