CBCT Guided Markerless SBRT for Renal Cell Cancer (CT-STARRS)

April 3, 2026 updated by: E. (Euphemia) A.M. Froklage, Erasmus Medical Center

Organ Sparing Marker-less CBCT-guided Stereotactic Adaptive Radiotherapy for Primary Non-metastasized Renal Tumors

This study aims to improve the treatment of kidney tumors using radiotherapy, by investigating whether kidney cancer can be more effectively irradiated with the help of new imaging techniques

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

In total 40 patients will be treated for RCC using SBRT.

For 15 patients, additional breath-hold CBCT scans will be made during SBRT to investigate the intra- and inter-fraction uncertainty in breath-hold positions as well as assessing the feasibility of using surface guidance as a surrogate for target position.

Subsequently, 25 patients will be treated using the new motion management technique developed using the extra imaging data obtained from the first cohort of patients. It is hypothesized that either breath-hold or gating in combination with surface guidance will result in a reproducible (stable) position of the target and therefore minimal margins.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients with histologically proven non-metastastic RCC or high suspicion of RCC based on imaging without histological evidence
  • No metastatic lesions
  • Patients must be 18 years or older
  • Ability to understand the requirements of the study and to give written informed consent, as determined by the treating physician.

Written informed consent

Exclusion Criteria:

  • Previous high-dose radiotherapy in the region of the kidney

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Additional imaging
Additional CBCT scans will be made after each fraction, follow-up will be done using photon counting CT
Radiation: Additional radiation due to imaging
Additional imaging will be done using CT, therefore the patient will receive additional radiation dose

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reduction of renal dose
Time Frame: At day 1 planning CTs are acquired for treatment planning. These scans will be used to make a treatment planning with standard motion management and a treatment planning will be made using novel motion management. Both plans will be compared.
The primary aim of this project is to minimize treatment margins, reducing the PTV, to optimally preserve renal function, while ensuring adequate tumor coverage as well as adhering to dose constraints of OARs. Primary endpoint of this study is the reduction of dose to the healthy ipsilateral kidney, defined as the ipsilateral renal volume receiving 50% of the prescribed dose (V50%).
At day 1 planning CTs are acquired for treatment planning. These scans will be used to make a treatment planning with standard motion management and a treatment planning will be made using novel motion management. Both plans will be compared.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evaluate the current treatment, including the benefit of online adaptive radiotherapy
Time Frame: Day 1 planning CTs. Approximately day 14: start radiotherapy (3 times per week). At each fraction: CBCT. At completion of treatment (at approximately day 30) planning for adapted and non-adapted plans
The possible benefit of online adaptive radiotherapy will be assessed by doing an offline analysis by comparing target coverage in % between adapted and non-adapted, original plans
Day 1 planning CTs. Approximately day 14: start radiotherapy (3 times per week). At each fraction: CBCT. At completion of treatment (at approximately day 30) planning for adapted and non-adapted plans
Investigate treatment fraction reduction
Time Frame: At day 1 planning CTs are acquired for treatment planning. These will be used for treatment planning for simulated fraction schedules using standard and novel motion management
the feasibility of transitioning from a 5×8 Gy schedule to 3×14 Gy or 1×26 Gy will be investigated by simulating the difference in the mean number of fractions when using SoC motion management and the novel motion management
At day 1 planning CTs are acquired for treatment planning. These will be used for treatment planning for simulated fraction schedules using standard and novel motion management
Change From Baseline in Tumor Contrast Enhancement on Photon-Counting CT
Time Frame: Baseline (pre-treatment) and follow-up at 3, 6, and 12 months after completion of treatment
Tumor contrast enhancement measured on contrast-enhanced photon-counting CT scans. Enhancement values will be quantified within the treated lesion and reported as change from baseline.
Baseline (pre-treatment) and follow-up at 3, 6, and 12 months after completion of treatment
Change From Baseline in Tumor Iodine Concentration on Photon-Counting CT
Time Frame: Baseline (pre-treatment) and follow-up at 3, 6, and 12 months after completion of treatment
Iodine concentration quantified within the treated lesion using material decomposition from contrast-enhanced photon-counting CT scans. Values will be reported as change from baseline.
Baseline (pre-treatment) and follow-up at 3, 6, and 12 months after completion of treatment

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Monitor side effects
Time Frame: During treatment and at 3, 6, and 12 months after completion of treatment
Side-effects are assessed during treatment and follow up, according to Common Terminology Criteria for Adverse Events version 5 (CTC-AE version 5).
During treatment and at 3, 6, and 12 months after completion of treatment
Monitor renal function
Time Frame: At 3, 6, and 12 months after treatment, followed by biannual evaluations at the referring center (referring urologist) in the second year and annual assessments in the third and fourth years
Renal function changes will be measured using estimated glomerular filtration rate (eGFR)
At 3, 6, and 12 months after treatment, followed by biannual evaluations at the referring center (referring urologist) in the second year and annual assessments in the third and fourth years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Erasmus Medical Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 1, 2026

Primary Completion (Estimated)

January 1, 2030

Study Completion (Estimated)

January 1, 2030

Study Registration Dates

First Submitted

September 30, 2025

First Submitted That Met QC Criteria

February 10, 2026

First Posted (Actual)

February 11, 2026

Study Record Updates

Last Update Posted (Actual)

April 8, 2026

Last Update Submitted That Met QC Criteria

April 3, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NL-010279

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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