A Prospective Randomized Controlled Study Comparing 68Ga-FAPI PET-Guided Abdominal Radiotherapy Combined With Second-Line Standard Therapy and Cadonilimab Versus Second-Line Standard Therapy in Colorectal Cancer With Peritoneal Metastasis
Main objective: 1\. To compare the objective response rate (ORR) of 68Ga-FAPI PET-guided abdominal region radiotherapy combined with second-line standard treatment versus cabozantinib and second-line standard treatment in the treatment of peritoneal metastasis of colorectal cancer. Secondary objectives: 1. To compare the disease control rate (DCR), duration of continuous remission (DoR), progression-free survival (PFS), and overall survival (OS) of 68Ga-FAPI PET-guided abdominal region radiotherapy combined with second-line standard treatment versus cabozantinib and second-line standard treatment in the treatment of peritoneal metastasis of colorectal cancer. 2. To evaluate the safety and tolerability of 68Ga-FAPI PET-guided abdominal region radiotherapy combined with second-line standard treatment versus cabozantinib.
• 1\. Age of 18 years or older. 2. Peritoneal metastasis of colorectal cancer confirmed by histological or cytological examination (International Union Against Cancer 8th edition of colorectal cancer staging).
• 3\. Progression after receiving standard first-line treatment before enrollment; but excluding any type of immunotherapy.
• 4\. Eastern Cooperative Oncology Group (ECOG) score of 0-1, with an expected survival time of more than 6 months.
• 5\. ECOG score of 0-1. 6. Expected survival time of ≥ 24 weeks. 7. Laboratory tests for bone marrow, liver and kidney organ functions and coagulation function within 7 days before the first administration were in compliance with the study requirements (no blood transfusion, blood products, use of granulocyte colony-stimulating factor or other hematopoietic stimulating factors for correction within 7 days before the laboratory tests).
• 8\. Women with reproductive capacity must have a negative blood pregnancy test result within 7 days before the first administration. Male or female patients with reproductive capacity voluntarily use effective contraceptive methods during the study period and within 6 months after the last study medication, such as double barrier contraceptive methods, condoms, oral or injectable contraceptive drugs, intrauterine devices, abstinence, etc. All female patients will be considered to have reproductive capacity, unless the female patient has naturally menopause, artificial menopause or sterilization (uterus removal, bilateral ovary removal).
• 9\. Voluntary enrollment and signing of informed consent form, following the trial treatment plan and visit schedule.