NCT07495293

Ultra-hypofractionated Carbon-ion Therapy for Prostate Cancer

Carbon-ion Therapy With Ultra-hypofractionated RadiothErapy for Localized Prostate Cancer (CURE-PC-1): Phase I Clinical Trial

• Status: Not Yet Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: Yonsei University · Academic / Other
• Sex: All
• Age: 19 Years
• Healthy volunteers: Not accepted

Summary

This is a single-arm, exploratory phase I clinical trial evaluating the safety and efficacy of ultra-hypofractionated carbon ion radiotherapy (CIRT) in 6 fractions compared to the conventional 12-fraction regimen in patients with low- and intermediate-risk localized prostate cancer. A total of 20 patients will be enrolled sequentially and treated with CIRT at 7 GyE per fraction, delivered twice weekly on alternating days, for a total of 6 fractions (total prescribed dose: 42 GyE). Androgen deprivation therapy for 6 months will be administered concurrently in patients classified as unfavorable intermediate-risk. The primary endpoint is the incidence of acute treatment-related toxicity of Grade 3 or higher per CTCAE v5.0 occurring within 90 days after completion of CIRT. Secondary endpoints include the incidence of late toxicity, biochemical relapse-free survival (bRFS), and quality of life assessed by EPIC-26 and IPSS questionnaires. Patients will undergo scheduled follow-up visits for 2 years after treatment completion, followed by long-term follow-up through electronic medical record review up to 5 years.

Detailed description

STUDY DESIGN This study is a prospective, single-arm clinical study designed to evaluate the safety of an ultra-hypofractionated carbon ion radiotherapy (CIRT) regimen in patients with localized prostate cancer. A total of 20 participants will be enrolled sequentially at a single institution. An initial cohort of 10 participants will be enrolled first. If fewer than 2 participants develop Grade ≥3 treatment-related acute toxicity within 90 days of completing CIRT, an additional 10 participants will be enrolled to reach the total sample size of 20. Participants will receive CIRT according to the following procedures. 1. Carbon Ion Radiotherapy : CIRT will be administered at 7 GyE per fraction, twice weekly on alternating days, for a total of 6 fractions over 3 weeks (total prescribed dose: 42 GyE). At the investigator's discretion, a simultaneous integrated boost (SIB) of 6 GyE × 6 fractions (total 36 GyE) may be prescribed to the seminal vesicle target. Treatment planning will be performed using RayStation with consideration of dose constraints for the rectum and bladder. 2. Androgen Deprivation Therapy (ADT) : ADT will not be administered to low-risk and favorable intermediate-risk patients. Unfavorable intermediate-risk patients will receive ADT concurrently for a total of 6 months, with the first dose completed prior to CIRT initiation. Permitted agents include GnRH agonists (Leuprolide, Goserelin, Triptorelin), GnRH antagonists (Degarelix, Relugolix), and anti-androgens (Bicalutamide, Flutamide, Nilutamide). 3. Permitted Procedures : Insertion of gold fiducial markers for image-guided radiotherapy and SpaceOAR hydrogel for rectal protection are permitted as part of the institutional standard of care and are not considered part of the study intervention.

Conditions

• Prostate Cancer

Interventions

Type	Name	Description
RADIATION	ultra-hypofractionated carbon ion therapy	Participants will receive carbon ion radiotherapy with a total prescribed dose of 42 GyE, delivered as 7 GyE per fraction over six fractions, administered twice weekly (every other day)

Timeline

• Start date: 2026-03-24
• Primary completion: 2029-12-31
• Completion: 2031-03-08
• First posted: 2026-03-27
• Last updated: 2026-03-27