Stereotactic Body Radiotherapy vs Moderately Hypofractionated IMRT for Localized Intermediate-Risk Prostate Cancer: A...

Area of Science:

• Radiation Oncology
• Urologic Oncology
• Clinical Trials

Background:

• Radiotherapy is a key treatment for prostate cancer, with evolving delivery methods.
• Assessing the risks and benefits of different radiotherapy techniques is crucial for patient care.

Purpose of the Study:

• To compare stereotactic body radiotherapy (SBRT) against moderately hypofractionated intensity-modulated radiation therapy (MH-IMRT) for localized prostate cancer.
• To evaluate differences in patient-reported urinary and bowel quality of life and disease-free survival (DFS).

Main Methods:

• A phase-3, international, randomized clinical trial (NRG-GU005) involving 698 patients.
• Patients were assigned to either SBRT (36.25 Gy in 5 fractions) or MH-IMRT (70 Gy in 28 or 60 Gy in 20 fractions).
• Primary outcomes included minimal clinically important decline (MCID) in urinary and bowel domains of the EPIC-26 instrument at 2 years and DFS at 3 years.

Main Results:

• SBRT showed improved urinary incontinence and sexual function at 1-2 years post-treatment.
• Fewer grade 3+ genitourinary adverse events were observed with SBRT (0.6% vs 2.5%).
• Significantly fewer MCIDs in the bowel domain were reported with SBRT (34.9% vs 43.8%, P=.03), but DFS at 3 years was lower for SBRT (88.6%) compared to MH-IMRT (92.1%, P<.001).

Conclusions:

• SBRT improved certain quality-of-life aspects, particularly bowel function, compared to MH-IMRT.
• Despite quality-of-life benefits, SBRT was not superior to MH-IMRT in achieving disease-free survival for prostate cancer.
• The rate of prostate-specific antigen (PSA) failure was not significantly improved with SBRT.