An interventional study of SBRT with adaptive fractionation and Standard of Care (SOC) in Abdominal Tumor and Pelvic Tumor, sponsored by University of Zurich. Recruiting at 1 site in Switzerland. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-07.
Sponsored by University of Zurich · Not applicable, Interventional, and Treatment
SBRT delivers high-dose radiation to precisely defined target volumes and is an effective locally ablative treatment option for both primary tumours and oligometastases in various settings, including lesions in the abdomen or pelvis. However, SBRT in these regions faces considerable challenges such as inter-fractional organ motion and anatomical deformation, which can compromise treatment precision.
MR-guided SBRT offers a solution, providing superior soft-tissue contrast and enabling real-time, online treatment plan adaptation over the course of SBRT. This approach reduces the risk of geographical miss and overdose to adjacent, vulnerable OARs. Currently, MR-guided SBRT uses a fixed dose per fraction, only adjusting target volume and OAR contours for anatomical changes when performing plan adaptation. However, overlaps between planning target volumes (PTVs) and dose-limiting OARs regularly require compromises in PTV coverage. To address this, AF aims to also adjust dose per fraction based on daily PTV-OAR overlap. With this approach, more dose is applied on treatment days with less PTV-OAR overlap while less dose is applied on days with more PTV-OAR overlap. This trial assesses the feasibility of AF in MR-guided SBRT for abdominal and pelvic tumours that show PTV-overlap with one or more dose-limiting OARs, ultimately aiming to enhance PTV dose coverage without increasing toxicity.
42 studies on the registry are indexed under Abdominal Neoplasms; 14 are open to participants now.
This study's planned enrollment of 100 is above the median of 78 across 26 interventional studies indexed under Abdominal Neoplasms.
Browse Abdominal Neoplasms studies →University of Zurich is the lead sponsor of 1,049 studies on the registry; 133 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Karnofsky performance status (KPS)
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with PTV/OAR overlap will receive AF, with dose adapted daily based on anatomy.
Radiation: SBRT with adaptive fractionation
Patients without PTV/OAR overlap will receive standard fractionated treatment.
Radiation: Standard of Care (SOC)
The fraction dose to the PTV will be adapted based on the volume overlap of PTV and the dose-limiting OAR(s) (bowel / duodenum / stomach) on the planning MRI scan of the day ("geometry-of-the-day"). The treatment plan is then approved by the treating physician and independently verified according to department-internal standard. MR-guided fraction dose adaptation will be repeated at each of the 5 fractions, until the prescribed total dose is reached.
Patients that qualify for inclusion in the study but for whom AF is no viable treatment due to lacking PTV/OAR overlap in the planning scans. These patients are treated according to clinical standard of care (SoC), i.e. without dose adaptation, and function as a control group.
Proportion of patients with successful daily dose adaptation
Proportion of patients treated with daily dose-adapted treatment, who received at least one fraction of non-uniformly fractionated treatment with expectation of a benefit in PTV-coverage of ≥ 1ccGy
Time frame: from enrollment to end of treatment at 1-2 weeks
Acute treatment toxicities
Acute treatment toxicities for all included patients measured with Common Terminology Criteria for Adverse Events
Time frame: during treatment (1-2 weeks) and until 90 days after
Interfractional variation in PTV/OAR overlap volume
interfractional variation in PTV/OAR overlap volume, in cc
Time frame: during treatment (1-2 weeks)
Interfractional variation in GTV/OAR distance
interfractional variation in GTV/OAR distance, in mm
Time frame: during treatment (1-2 weeks)
Dosimetric difference in PTV-coverage between algorithm-based calculation and the reference plan
PTV coverage quantified as the area above the dose-volume-histogram curve measured in cc x Gy
Time frame: after end of treatment (2 weeks after last fraction)
Plan to share: No
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Dec 2028, 30 months after the start.
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