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Daily Adjustment of the Radiation Dose in MRI-guided Stereotactic Radiotherapy for Tumors in the Abdominal and Pelvic Regions (ACTION)

29 juni 2026 uppdaterad av: University of Zurich

Adaptive Fractionation in Online MR-guided SBRT for Abdominal and Pelvic Target Volumes

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.

Studieöversikt

Status

Rekrytering

Betingelser

Intervention / Behandling

Studietyp

Interventionell

Inskrivning (Beräknad)

100

Fas

  • Inte tillämpbar

Kontakter och platser

Det här avsnittet innehåller kontaktuppgifter för dem som genomför studien och information om var denna studie genomförs.

Studiekontakt

  • Namn: Jan Unkelbach, Prof. Dr. rer. nat.
  • Telefonnummer: +41 44 255 85 49
  • E-post: jan.unkelbach@usz.ch

Studera Kontakt Backup

Studieorter

  • Schweiz
    • Canton of Zurich
      • Zurich, Canton of Zurich, Schweiz, 8091
        • Rekrytering
        • University Hospital Zurich

Deltagandekriterier

Forskare letar efter personer som passar en viss beskrivning, så kallade behörighetskriterier. Några exempel på dessa kriterier är en persons allmänna hälsotillstånd eller tidigare behandlingar.

Urvalskriterier

Åldrar som är berättigade till studier

  • Vuxen
  • Äldre vuxen

Tar emot friska volontärer

Nej

Beskrivning

Inclusion Criteria:

  • Karnofsky performance status ≥70
  • Abdominal or pelvic malignancy (primary or secondary) with previous histological confirmation of the primary tumour, amenable to SBRT in 5 fractions (excluding SBRT to primary tumour in patients with prostate cancer) Note: patients with primary prostate cancer are eligible, but SBRT to the primary tumour in the prostate cannot be performed within the study
  • Total prescribed SBRT dose > 30 Gy (constraint for dose-limiting OAR) over 5 treatment fractions
  • Distance of the GTV ≤ 1 cm from at least one dose-limiting OAR (bowel / duodenum / stomach) in the available diagnostic images
  • Patients able to tolerate long (approximately 60 minutes) treatment time according to clinical evaluation of the treating radiation oncologist
  • Patients willing and able to comply with scheduled visits, treatment, and other trial procedures

Exclusion Criteria:

  • Previous radiation therapy directly overlapping with planned SBRT (type I re-irradiation)
  • More than one PTV irradiated in the same plan
  • Contraindications for MRI, e.g., patients with metal fragments or implanted devices that are not MR compatible such as certain types of pacemakers and aneurysm clips or severe claustrophobia
  • SBRT not indicated or not possible
  • Inability to follow the procedures of the trial, e.g. due to language problems of the participant

Studieplan

Det här avsnittet ger detaljer om studieplanen, inklusive hur studien är utformad och vad studien mäter.

Hur är studien utformad?

Designdetaljer

  • Primärt syfte: Behandling
  • Tilldelning: Icke-randomiserad
  • Interventionsmodell: Parallellt uppdrag
  • Maskning: Ingen (Open Label)

Vapen och interventioner

Deltagargrupp / Arm
Intervention / Behandling
Experimentell: RT with AF
Patients with PTV/OAR overlap will receive AF, with dose adapted daily based on anatomy.
Strålning: SBRT with adaptive fractionation
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.
Aktiv komparator: RT without AF
Patients without PTV/OAR overlap will receive standard fractionated treatment.
Strålning: Standard of Care (SOC)
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.

Vad mäter studien?

Primära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Proportion of patients with successful daily dose adaptation
Tidsram: from enrollment to end of treatment at 1-2 weeks
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
from enrollment to end of treatment at 1-2 weeks

Sekundära resultatmått

Resultatmått
Åtgärdsbeskrivning
Tidsram
Acute treatment toxicities
Tidsram: during treatment (1-2 weeks) and until 90 days after
Acute treatment toxicities for all included patients measured with Common Terminology Criteria for Adverse Events
during treatment (1-2 weeks) and until 90 days after
Interfractional variation in PTV/OAR overlap volume
Tidsram: during treatment (1-2 weeks)
interfractional variation in PTV/OAR overlap volume, in cc
during treatment (1-2 weeks)
Interfractional variation in GTV/OAR distance
Tidsram: during treatment (1-2 weeks)
interfractional variation in GTV/OAR distance, in mm
during treatment (1-2 weeks)
Dosimetric difference in PTV-coverage between algorithm-based calculation and the reference plan
Tidsram: after end of treatment (2 weeks after last fraction)
PTV coverage quantified as the area above the dose-volume-histogram curve measured in cc x Gy
after end of treatment (2 weeks after last fraction)

Samarbetspartners och utredare

Det är här du hittar personer och organisationer som är involverade i denna studie.

Sponsor

University of Zurich

Utredare

  • Huvudutredare: Reinhardt Krcek, Dr. med., University of Zurich

Studieavstämningsdatum

Dessa datum spårar framstegen för inlämningar av studieposter och sammanfattande resultat till ClinicalTrials.gov. Studieposter och rapporterade resultat granskas av National Library of Medicine (NLM) för att säkerställa att de uppfyller specifika kvalitetskontrollstandarder innan de publiceras på den offentliga webbplatsen.

Studera stora datum

Studiestart (Faktisk)

16 juni 2026

Primärt slutförande (Beräknad)

1 december 2028

Avslutad studie (Beräknad)

1 december 2028

Studieregistreringsdatum

Först inskickad

30 april 2026

Först inskickad som uppfyllde QC-kriterierna

29 juni 2026

Första postat (Faktisk)

7 juli 2026

Uppdateringar av studier

Senaste uppdatering publicerad (Faktisk)

7 juli 2026

Senaste inskickade uppdateringen som uppfyllde QC-kriterierna

29 juni 2026

Senast verifierad

1 juni 2026

Mer information

Termer relaterade till denna studie

Nyckelord

Ytterligare relevanta MeSH-villkor

Andra studie-ID-nummer

  • RAO-25-019
  • 2026-00067 (Annan identifierare: BASEC)

Plan för individuella deltagardata (IPD)

Planerar du att dela individuella deltagardata (IPD)?

NEJ

Läkemedels- och apparatinformation, studiedokument

Studerar en amerikansk FDA-reglerad läkemedelsprodukt

Nej

Studerar en amerikansk FDA-reglerad produktprodukt

Nej

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