Clinical trials

Feas_SBRT_Lung: Surface and X-ray guided stereotactic Body Radiotherapy for lung lesions using a breath-hold technique

Research goals

Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumors with minimal impact on surrounding healthy tissue, offering a non-surgical alternative. However, lung tumors present challenges due to movement caused by breathing, traditionally requiring fiducial markers to track motion. At UZ Brussel, we aim to overcome these limitations by developing a markerless SBRT approach using ExacTrac Dynamic technology. This system integrates thermal and surface cameras with stereoscopic x-rays to synchronize treatment with the patient’s breathing, enabling precise and non-invasive care. Our goal is to expand SBRT access, reduce treatment uncertainties, and improve outcomes while minimizing healthy tissue exposure.

Outcomes

The primary endpoint is feasibility of breath-hold markerless irradiation by evaluating:

• Simulation and treatment duration
• Ability to visualize and position the lesion with x-ray imaging by comparing the data against
• the clinical protocol/workflow of gated CBCT.
• Lesions that benefit the highest (i.e. influence of the lesion location, PTV volume, …)
• Normal tissue doses comparing BH treatments, vs standard “free breathing” 4DCT-based
• techniques
• Patient compliance (or breath-hold reproducibility) throughout treatment course

Secondary endpoints include local control at 1 year and physician reported late toxicity.

Sample size

For this feasibility study 24 patients with lung lesions will be treated.

Feas_Cran_Mask: Evaluation of an open immobilization device for intracranial treatments and feasibility of SGRT monitoring

Research goals

This study investigates the use of open immobilization masks for intracranial radiotherapy, which promise improved patient comfort and enhanced monitoring compared to traditional closed masks. Closed masks are effective in immobilizing the head but can cause significant discomfort and anxiety, particularly during extended treatment regimens. Open masks, which expose parts of the face, may improve patient experience and enable real-time surface-guided radiotherapy (SGRT) monitoring. However, their effectiveness in maintaining accurate and reproducible head positioning has not been thoroughly evaluated. This study aims to assess the immobilization performance of open masks compared to closed masks, while also exploring their potential benefits in patient comfort and treatment monitoring.

Outcomes

The primary endpoint is measuring positioning errors when fixating with both masks (immobilization effectiveness) and SGRT Feasibility:

• Measure intra-fractional positioning errors in six degrees of freedom (6DOF) using stereoscopic x-rays. Hypothesis: Closed and open masks show no significant differences in positioning error distribution. Positioning Errors (Immobilization Effectiveness)
• Assess the correlation between SGRT-measured positioning errors (using open masks) and x-ray-derived errors in 6DOF. SGRT Feasibility

Secondary endpoints include measuring the patient comfort and distressvia evaluating levels of pain, discomfort, and anxiety using post-treatment surveys. Our hypothesis is that open masks improve comfort, reduce distress, and enhance overall satisfaction compared to closed masks without introducing additional positioning errors.

Sample size

For this feasibility 40 patients with cranial lesions will be treated.

PROSEVEN: MR-guided prostate stereotactic body radiotherapy in seven days (NCT04896801)

Research goals

Stereotactic body radiotherapy (SBRT) is an established treatment for low- and intermediate-risk prostate cancer, delivering high doses with MR-guided precision. A standard dose of 40 Gy in 5 fractions to the prostate and 36.25 Gy to the planning target volume (PTV) is commonly used, though the impact of treatment time on outcomes, toxicity, and quality of life remains unclear. Recent data suggest a benefit of a focal boost to the dominant intraprostatic lesion. The Proseven-study enrolls patients with low- to limited high-risk prostate cancer, excluding those with large prostates, severe urinary symptoms, or hip prostheses. Patients will receive MR-guided SBRT in 5 daily fractions over 7 days, with a simultaneous integrated boost to the dominant lesion.

Outcomes

The primary endpoint is physician reported acute gastrointestinal (GI) and genitourinary (GU) toxicity.

Secondary endpoints include physician reported late GI & GU toxicity, patient reported outcomes and quality of life assessment and treatment efficacy parameters (freedom from biochemical failure, disease-free survival, overall survival).

Sample size

In total 132 patients will be enrolled to examine the feasability of MR-guided stereotactic radiotherapy to the prostate using an overall treatment time of 7 days.

TNTRect: Total Neoadjuvant Treatment of Rectal Cancer by MRI-guided Radiotherapy (NCT05916040)

Research goals

This study investigates the efficacy of short-course MRI-guided radiotherapy (5×5 Gy) with a simultaneous integrated boost (SIB) (5×6 Gy) for treating locally advanced rectal cancer. The RAPIDO trial [1,2] showed improved disease-related outcomes with short-course radiotherapy followed by chemotherapy but noted higher locoregional recurrence rates. To address this, we applied MRI-guided adaptive radiotherapy together with a SIB on the Gross Tumour Volume (GTV) to enhance local control by delivering a targeted dose to the tumor.

After radiotherapy and chemotherapy are administered, the patient will be evaluated for a potential watchful-waiting approach where, together with the patient, can be opted too not perform a TME (total mesorectal excision) – the typical procedure for removing the affected part of the rectum and surrounding tissue. This approach aims to preserve rectal function and improve quality of life while ensuring effective disease management, provided there is a complete clinical response (cCR) to the treatment.

[1]: Bahadoer RR et al.; Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO): a randomised, open-label, phase 3 trial. Lancet Oncol. 2021 Jan;22(1):29-42. link

[2]: Dijkstra EAet al.; Locoregional Failure During and After Short-course Radiotherapy Followed by Chemotherapy and Surgery Compared With Long-course Chemoradiotherapy and Surgery: A 5-Year Follow-up of the RAPIDO Trial. Ann Surg. 2023 Oct 1;278(4):e766-e772. link

Outcomes

The primary endpoint is (a) response to this therapy (local control, disease free survival and overall survival) and (b) the number of patients without surgical procedure to remove the affected part that remains under (local) control.

Secondary endpoints include physician reported late GI & GU toxicity and patient reported outcomes (EORTC QLQ-C30, EORTC QLQ-CR29, the level of hospital anxiety and depression (via HADS) and LARS questionnaire).

Sample size

In total 35 patients will be enrolled to examine the feasability of MR-guided stereotactic radiotherapy to the rectum using an overall treatment time of 7 days to guarantee a preservation of the rectum.

Research goals

Preoperative (chemo)radiotherapy is the standard of care in locally advanced rectal cancer and results in an excellent local tumor control. However, the response to preoperative chemoradiotherapy is heterogeneous and remains unpredictable. Patients with a complete clinical remission (CCR) may profit from a watchful-waiting approach.

The MRIdian is a novel radiation platform that integrates a 0,35 Tesla MRI-scan for daily imaging on the treatment couch and adaptive radiotherapy. Its high precision will allow dose escalation on rectal tumors to increase the CCR rate.

The aim of the study is to build an artificial intelligence model based on radiomics data retrospectively collected of the simulation scans of rectal cancer patients treated at UZ Brussel. This model will be used to predict the response of rectal cancer to pre-operative radiotherapy and chemo-radiotherapy. The results of this study can be used as a basis for patient-specific dose prescription on the MRIdian in the near future.

Outcomes

Accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of the prediction model

Research goals

This Phase IIIb trial compares two types of androgen deprivation therapy (ADT) in prostate cancer patients requiring combined radiotherapy and long-term ADT. Eligible patients include those with high-risk localized, locally advanced, oligometastatic prostate cancer, or those undergoing salvage radiotherapy post-prostatectomy.

Prostate cancer growth is driven by androgens, including testosterone, which ADT inhibits. Radiotherapy efficacy improves when combined with ADT. The trial evaluates LHRH-agonists (leuproreline, gosereline, triptoreline), a standard therapy with an initial testosterone surge requiring antiandrogens, and LHRH-antagonists (degarelix), which lack this surge and may offer fewer side effects.

ADT is administered before, during, and after radiotherapy, except in salvage therapy where both start simultaneously. Treatment duration is 6, 18, 24, or 36 months, based on clinical decisions. Follow-up involves quality-of-life questionnaires, physical assessments, PSA, testosterone levels, and an ECG at 3 months.

The study includes a translational research component with optional saliva collection for genetic testing to explore links between genetic changes, side effects, and treatment outcomes.