Abstract:Objective To analyze the prognostic characteristics of different invasion sites and the risk factors affecting overall prognosis, in patients with pT_4b stage colorectal cancer who underwent radical resection and showed no lymph node metastasis （N₀） by pathology. Methods The clinical and pathological data of colorectal cancer patients received surgical resection in China National Petroleum Corporation Central Hospital from 2017-01-01 to 2021-12-21 were calculated and followed up to 2022-12-31. The time of operation, the time of local recurrence or distant metastasis and the time of death were recorded. Risk factor analysis was grouped based on whether there was disease progression during follow-up. Prognosis of different groups was compared and logistic binary regression was used to screen for meaningful risk factors. Results Survival analysis showed that the disease-free survival (DFS) of patients with tumor invasion of abdominal wall or omentum was (22.2±3.2) months, DFS of tumor invasion of stomach or intestine was (28.3±5.6) months, DFS of tumor invasion of uterus or adnexal was (35.7±2.6) months, and DFS of tumor invasion of the bladder or ureteral was (30.1±3.4) months, Log-rank P=0.001 among groups. Multivariate analysis showed that the right colon (OR=6.829, 95%CI:1.603-29.093, P=0.009), tumor invasion of abdominal wall, omentum (OR=6.198, 95%CI:1.231-31.210, P=0.027), tumor maximum diameter (OR=0.565, 95%CI:0.365-0.874, P=0.010) were independent factors affecting the progression of colorectal cancer. Conclusion Among colorectal cancer patients with pathological staging pT_4bN₀M₀, patients with tumor invasion of the uterus and appendix have the best prognosis, while patients with invasion of the abdominal wall and omentum have the worst prognosis. Patients with tumors located in the right colon and invading the abdominal wall, omentum, or smaller tumor lesions are more likely to experience regional recurrence or distant metastasis after surgery.