Assuming that the objective response rate (ORR) of neoadjuvant chemotherapy in patients with colorectal cancer peritoneal metastasis is approximately 0.40 , a total sample size of 30 patients is required.
Step 1:
Ten patients will be initially enrolled. If the number of responders (CR/PR) is \< 2, the study will be terminated early for futility.
If the number of responders is \> 8, the treatment regimen will be considered effective, and the study may be concluded early.
Step 2:
If the number of responders in Step 1 is between 2 and 8, the study will continue to enroll an additional 20 patients until completion.
Treatment regimen: CapeOX + Pirfenidone + Sintilimab
CapeOX:
Oxaliplatin (L-OHP) 130 mg/m², IV infusion over 2 hours on Day 1 Capecitabine 1,000 mg/m² orally, twice daily for 14 consecutive days Repeated every 3 weeks
Pirfenidone:
Oral administration, 200 mg three times daily, taken on an empty stomach (low-dose regimen)
Sintilimab:
200 mg per dose, IV infusion once every 3 weeks The first 4 cycles are provided free of charge. After the fourth cycle, tumor response will be assessed; if continued use is required, a "buy 2, get 2 free" policy will apply.
Tumor response evaluation will be performed after 4 treatment cycles.