Weekly Online CT or MR Adaptive Definitive SBRT for Very High Risk Localized or Regionally Metastatic Prostate Cancer

NCT07591051 | Not Yet Recruiting

• 1 other identifier: RAO-24-033
• Study Type: interventional
• Target: 54
• Locations: 2 countries
• Sites: 2

Brief Summary

This interventional prospective multicenter international study will include 54 patients with very high-risk localized (cN0 cM0) or regional (i.e. cN1 cM0) prostate cancer according the NCCN criteria. Patients will be treated with weekly CT or MR-informed online adaptive SBRT of the prostate and elective pelvic lymph nodes with 5 x 5 Gy. In the case of regional lymph nodes, a simultaneous integrated boost (SIB) of involved lymph nodes will be performed with 5 x 6.5 Gy. In the case of up to 2 dominant intraprostatic lesion (DIL) a SIB of the DIL with 5 x 9 Gy can be performed (optional). Importantly, coverage of these DIL volumes must be compromised as needed to respect OAR constraints. This study is classified as risk category A according to ClinO, Art. 61, as stereotactic radiotherapy (SBRT) for localized or regional prostate cancer has been extensively evaluated in prospective interventional trials and is considered an established therapeutic modality. Weekly CT- or MR-guided online adaptive SBRT to the prostate and elective pelvic lymph nodes with 5 × 5 Gy is, however, not yet routinely implemented for this specific patient population. A diagnostic high field MRI during radiotherapy, e.g. week 3 is optional. Follow-up is also according to standard of care (except for patient reported outcome measure using QLQ-C30 and QLQ-PR25 and a diagnostic MRI at 9 months after SBRT (optional), and 12 months in the case of an image non-complete response at 9 months (optional).

Conditions

Prostate Cancer

Outcome Measures

Primary Outcomes (2)

• Feasibility- a successful delivery of CT or MR-informed SBRT per fraction

  Feasibility will be assessed by recording whether each fraction of stereotactic body radiation therapy (SBRT), guided by computed tomography (CT) or magnetic resonance (MR) imaging, is successfully delivered according to the planned treatment parameters. Successful delivery is defined as completion of the planned fraction without protocol deviations or technical interruptions. Data will be summarized as the proportion of fractions successfully delivered per patient and overall. Every treatment fraction having passed the point of entry into the adaptive workflow will be analyzed for this endpoint.

  from Day 1 of treatment up to 7 weeks until end of treatment

• Safety - Adverse events

  The presence of genitourinary or gastrointestinal toxicity of grade ≥ 3 within 1 year after completion of radiotherapy (according to CTCAE v5.0). Treatment-related discontinuation. and Subgroup analyses will be performed for patients with and without regional lymph node metastases (i.e., cN0 versus cN1).

  ≥ 3 months to within 1 year after completion of SBRT

Secondary Outcomes (14)

• Biochemical progression-free survival

  from Day 1 up to 5 years after treatment

• Castration-resistant free survival

  from Day 1 up to 5 years after treatment

• Patients Quality of Life EQ-5D-5L from the European Organisation for Research and Treatment of Cancer

  from Day 1 up to end of study until 5 years

• Patients Quality of Life QLQ-C30 from the European Organisation for Research and Treatment of Cancer

  From Day 1 up to end of study (up to 5 years)

• Adverse events

  from Day 1 until 5 years or end of Study

Study Arms (1)

Single Group Study

OTHER

Assessment of weekly CT or MR-informed online adaptive SBRT of the prostate and elective pelvic lymph nodes with 5 x 5 Gy.

Device: weekly CT or MR online adaptive definitive SBRT

Interventions

weekly CT or MR online adaptive definitive SBRT DEVICE

Patients will be treated with weekly CT or MR-informed online adaptive SBRT of the prostate and elective pelvic lymph nodes with 5 x 5 Gy. In the case of regional lymph nodes, a simultaneous integrated boost (SIB) of involved lymph nodes will be performed with 5 x 6.5 Gy. In the case of up to 2 dominant intraprostatic lesion (DIL) a SIB of the DIL with 5 x 9 Gy can be performed (optional). Importantly, coverage of these DIL volumes must be compromised as needed to respect OAR constraints.

Single Group Study

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: This study will include male patients only since male patients only are able to get prostate cancer.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Very high risk localized defined (cN0) according to NCCN guidelines consisting of ≥2 of the following:
• cT3 disease and/or
• Gleason 8-10 and/or
• PSA ≥40 (the baseline PSA value should be doubled for PSAs taken while on 5-alpha reductase inhibitors) OR
• Regionally metastatic prostate cancer (cN1, any T, any Gleason, any PSA) according to NCCN guidelines consisting of ≤3 lymph node metastases of any of the following:
• Obturator
• Internal iliac (hypogastric)
• External iliac nodes
• Presacral nodes
• Common iliac (below iliac bifurcation)
• Periprostatic/Perivesical AND
• Good to moderate performance status (WHO 0-2)
• Written informed consent.
• A PSMA PET and multiparametric MRI is mandatory according to staging guidelines.
• Age ≥ 18 years

You may not qualify if:

• ≥4 regional lymph nodes
• Patients with cT4 disease (tumor is fixed or invades adjacent structures other than seminal vesicles such as external sphincter, rectum, bladder, levator muscles, and/or pelvic wall)
• Previous RT to the pelvis or prostate
• Previous radical prostatectomy
• Large body size that would not fit into the MRI-simulator bore
• Presence of distant metastases (i.e. cM1)
• Non-regional lymph nodes (M1a):
• Common iliac
• Para-aortic / retroperitoneal
• Inguinal
• Mediastinal or supraclavicular
• Mesorectal
• Other
• Bone metastases (M1b)
• Other sites (M1c)

Sponsors & Collaborators

• University of Zurich: lead

Study Sites (2)

University Clinic Heidelberg

Heidelberg, Baden-Würtemberg, 69120, Germany

Location

University Hospital Zurich

Zurich, Canton of Zurich, 8091, Switzerland

Location

MeSH Terms

Conditions

Prostatic Neoplasms

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Study Officials

• Matthias Guckenberger

  Universitätsspital Zürich

  STUDY CHAIR

• Tiuri Kroese

  University of Zurich

  PRINCIPAL INVESTIGATOR

• Matthias Guckenberger

  University of Zurich

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Radiation Oncology Study Office

CONTACT

+41432534308; RAO_akademischesoffice@usz.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This interventional prospective multicenter international study will include 54 patients with very high-risk localized (cN0 cM0) or regionally metastatic (i.e. cN1 cM0) prostate cancer according the NCCN criteria. Patients will be treated according to clinical standard of care with weekly CT or MR-informed online adaptive SBRT of the prostate and elective pelvic lymph nodes with 5 x 5 Gy. In the case of regional lymph nodes, a simultaneous integrated boost (SIB) of involved lymph nodes will be performed with 5 x 6.5 Gy. In the case of up to 2 dominant intraprostatic lesion (DIL) a SIB of the DIL with 5 x 9 Gy can be performed (optional). Importantly, coverage of these DIL volumes must be compromised as needed to respect OAR constraints.

Study Record Dates

• First Submitted: March 11, 2026
• First Posted: May 15, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): July 1, 2033
• Last Updated: May 15, 2026

Record last verified: 2026-04

Locations

DE (1); CH (1)