Trial results for the PRE-ProstAtectomy MRI-GuidEd Stereotactic Body RadioTherapy for High-Risk Prostate Cancer Trial (PREPARE SBRT) were posted on ClinicalTrials.gov on 2026-03-18. The study, which enrolled 16 participants, reported that between 3 and 6 subjects across different treatment arms successfully completed radical prostatectomy after SBRT without a post-operative Grade 3 or higher dose-limiting toxicity (DLT).
Background
Prostate cancer is a common malignancy, with high-risk forms often characterized by a Gleason Score of 8 or greater or clinical/radiographic evidence of T3 disease. Radical prostatectomy is a standard treatment option for localized prostate cancer. The PREPARE SBRT trial investigates the safety and feasibility of stereotactic body radiotherapy (SBRT) administered prior to prostatectomy, aiming to explore its potential role in improving outcomes for patients with high-risk disease by reducing tumor burden or improving surgical margins.
Trial design
The PREPARE SBRT trial (NCT03663218) is listed as Phase NA and enrolled a total of 16 participants. The study focused on patients with Prostate Cancer, specifically those with a Gleason Score of 8 or greater or clinical/radiographic evidence of T3 disease. The trial evaluated different dose regimens of stereotactic body radiotherapy (SBRT) administered prior to radical prostatectomy. The intervention arms included SBRT at 5 Gy x 5 Fractions, 6 Gy x 5 Fractions, and 6.5 Gy x 5 Fractions, along with an MTD Expansion Cohort.
Key results
The trial reported on the number of subjects who successfully completed radical prostatectomy after SBRT without a post-operative dose-limiting toxicity (DLT) of Grade 3 or higher in Part 1 of the study:
- In the Arm 5 Gy x 5 Fractions, 3 participants successfully completed the procedure without a Grade 3 or higher DLT.
- In the Arm 6 Gy x 5 Fractions, 3 participants successfully completed the procedure without a Grade 3 or higher DLT.
- In the Arm 6.5 Gy x 5 Fractions, 4 participants successfully completed the procedure without a Grade 3 or higher DLT.
- In the ARM MTD Expansion Cohort, 6 participants successfully completed the procedure without a Grade 3 or higher DLT.
What this means
These initial results from the PREPARE SBRT trial provide early insights into the safety and feasibility of neoadjuvant SBRT followed by radical prostatectomy for high-risk prostate cancer. The reported numbers indicate that participants across the various SBRT dose arms were able to undergo subsequent radical prostatectomy without experiencing severe post-operative dose-limiting toxicities (Grade 3 or higher). This suggests that the investigated SBRT regimens, when used prior to surgery, did not preclude successful surgical intervention or introduce unacceptable acute surgical complications in this small cohort. Further research would be needed to assess the efficacy of this approach in terms of oncological outcomes.
Source
The information for these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT03663218, titled "PRE-ProstAtectomy MRI-GuidEd Stereotactic Body RadioTherapy for High-Risk Prostate Cancer Trial (PREPARE SBRT)", were posted on 2026-03-18 on clinicaltrials.gov.