MRI-Guided Adaptive Radiotherapy for Limited Peritoneal Metastases (MARACAS Trial).

NCT07593261 | Not Yet Recruiting Phase 2 FDA Device

• 1 other identifier: 26983
• Study Type: interventional
• Target: 34
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective phase II study evaluates the efficacy and safety of MRI-guided stereotactic body radiotherapy (MRIgSBRT) in patients with oligometastatic peritoneal carcinomatosis from gastrointestinal or gynecological tumors. Eligible patients with up to 5 MRI-visible peritoneal lesions and PCI ≤20 will be treated with MRIgSBRT using a hybrid MRI-linear accelerator with online adaptive planning and real-time tumor tracking. The primary endpoint is radiologic response rate according to RECIST 1.1 criteria. Secondary endpoints include overall survival, progression-free survival, local control, chemotherapy-free survival, and treatment-related toxicity. The study aims to assess MRIgSBRT as a safe and non-invasive treatment option for selected patients with limited peritoneal metastatic disease.

Conditions

Peritoneal Carcinomatosis; Oligometastatic Disease; Peritoneal Metastases

Keywords

MRI-guided radiotherapy; Stereotactic body radiotherapy; Peritoneal carcinomatosis; Peritoneal metastases; Online adaptive radiotherapy

Outcome Measures

Primary Outcomes (1)

• Radiological Response Rate (RR)

  RR: The response rate will be calculated as the proportion of patients achieving a complete or partial radiological response out of the total number of evaluable patients according to RECIST 1.1 criteria

  Up to 12 months after completion of MRIgSBRT

Study Arms (1)

MRI-guided SBRT

EXPERIMENTAL

Patients with oligometastatic peritoneal carcinomatosis will receive MRI-guided stereotactic body radiotherapy (MRIgSBRT) delivered with a hybrid MRI-linear accelerator using online adaptive planning and real-time tumor tracking. Treatment dose will range from 30 to 50 Gy in 5 fractions according to clinical judgment and organ-at-risk constraints.

Device: MRI-guided stereotactic body radiotherapy

Interventions

MRI-guided stereotactic body radiotherapy DEVICE

Patients will receive MRI-guided stereotactic body radiotherapy (MRIgSBRT) delivered using a hybrid MRI-linear accelerator with online adaptive planning and real-time tumor tracking. Treatment will consist of 30-50 Gy delivered in 5 fractions according to clinical judgment, target characteristics, and organ-at-risk constraints. Daily adaptive replanning may be performed to account for anatomical changes and optimize dose delivery in patients with oligometastatic peritoneal carcinomatosis.

MRI-guided SBRT

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥18 years
• ECOG performance status 0-2
• Life expectancy ≥6 months
• Up to 5 MRI-visible peritoneal nodules
• PCI ≤20
• No prior radiotherapy in the same abdominal region within 6 months
• Signed informed consent
• History of prior CRS and/or HIPEC

You may not qualify if:

• Diffuse peritoneal carcinomatosis
• Psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule (those conditions should be discussed with the patient before registration in the trial)
• Significant comorbidities (such as: severe cardiac or coagulative disease, moderate or severe
• restrictive/obsiructive lung deficit, severe cognitive impairment, moderate and severe renal and hepatic impairment.
• Pregnancy or breastfeeding
• MRI contraindications (e.g., pacemaker, severe claustrophobia)

Sponsors & Collaborators

• Fondazione Policlinico Universitario Agostino Gemelli IRCCS: lead

Study Sites (1)

Gemelli ART (Advanced Radiation Therapy)-Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Roma, 000168, Italy

Location

MeSH Terms

Conditions

Peritoneal Neoplasms

Condition Hierarchy (Ancestors)

Abdominal Neoplasms; Neoplasms by Site; Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Peritoneal Diseases

Study Officials

• Luca Boldrini

  Fondazione Policlinico Universitario Agostino Gemelli IRCCS

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Luca Boldrini

CONTACT

+390630158195; luca.boldrini@policlinicogemelli.it

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 12, 2026
• First Posted: May 18, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): July 1, 2029
• Study Completion (Estimated): July 1, 2032
• Last Updated: May 18, 2026

Record last verified: 2026-05

Locations

IT (1)