Phase 2/3 prostate SBRT trial tests focal DIL boost vs whole-gland boost (ionizing radiation)

This Phase 2/3 randomized study from the University of Nebraska compares two linear-accelerator–based stereotactic body radiotherapy (SBRT) dose-escalation strategies for treatment‑naïve localized prostate cancer. Arm A escalates dose to the whole prostate (36.25 Gy to PTV with a simultaneous integrated boost to 40 Gy to prostate CTV in 5 fractions), while Arm B escalates dose specifically to the dominant intraprostatic lesion (DIL) using a simultaneous integrated boost approach. The intervention in both arms is external-beam ionizing radiation (DNA damage via double‑strand breaks) delivered with highly conformal planning to limit dose to bladder, urethra, and rectum. The primary scientific angle is whether “precision boosting” the MRI/target-defined DIL can reduce genitourinary and gastrointestinal toxicity without sacrificing tumor control, compared with escalating the entire gland. Today’s care for localized, treatment‑naïve prostate cancer is risk-adapted management including active surveillance for lower‑risk disease, or definitive prostatectomy or external-beam radiation (often with short‑ or long‑course androgen deprivation therapy for unfavorable/intermediate-high risk); this trial refines how SBRT dose escalation is delivered rather than adding a new systemic drug.