Main objective:
1\. To compare the objective response rate (ORR) of 18F-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 18F-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 18F-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).
1. Absolute neutrophil count (ANC) < 1.5 × 109/L, or platelet count < 100 × 109/L (for patients with liver metastasis, platelet count < 80 × 109/L), or hemoglobin < 9 g/dL; blood transfusion within 2 weeks prior to enrollment is not allowed to meet the inclusion criteria.