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.
Peritoneal carcinomatosis (PC) represents a frequent metastatic pattern in gastrointestinal and gynecological malignancies and is associated with poor prognosis and limited therapeutic options. Although cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) may improve outcomes in selected patients, many patients are not candidates for surgery because of recurrent disease, comorbidities, or poor performance status. MRI-guided stereotactic body radiotherapy (MRIgSBRT) allows highly conformal radiation delivery with online adaptive planning and real-time tumor tracking, potentially improving treatment precision and sparing surrounding organs at risk in anatomically complex abdominal sites. This prospective single-center phase II study will evaluate MRIgSBRT in patients with oligometastatic peritoneal carcinomatosis with up to 5 MRI-visible lesions and PCI ≤20. Treatment will be delivered using a hybrid MRI-linear accelerator with adaptive planning according to daily anatomical variations. 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 assessed according to CTCAE v5.0.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
34
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.
Gemelli ART (Advanced Radiation Therapy)-Fondazione Policlinico Universitario Agostino Gemelli IRCCS
Roma, Italy
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
Time frame: Up to 12 months after completion of MRIgSBRT
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