To investigate the risk factors of metachronous liver metastases after radical resection of colorectal cancer and the value of building a prediction model.

The clinical data of 130 patients who underwent radical colorectal cancer treatment during the period from June 2018 to June 2022 were retrospectively analysed. Patients were divided into metastatic group (30 cases) and non-metastatic group (100 cases) according to whether occult liver metastasis occurred during follow-up. SPSS 26.0 software was used for data analysis, single factor and multiple factor Logistic regression were used to analyze the risk factors affecting the occurrence of occulted liver metastases after radical resection of colorectal cancer, and independent risk factors were used to build a nomogram prediction model. Receiver operating characteristic curve (ROC) was drawn to evaluate the differentiation of the prediction model and verify the consistency of the prediction model. Take α=0.05 on both sides.

The incidence of occult liver metastasis was 23.1% in 130 patients. Preoperative CEA ≥5 μg/L, peripheral nerve invasion, low differentiation, vascular invasion, longest tumor diameter ≥5 cm, stage T_3-4 and stage N_1-2 in metastasis group were higher than those in non-metastatic group, and the differences were statistically significant (P < 0.05). Multiple Logistic regression analysis showed that CEA≥5 μg/L before surgery was the risk factor for metachronous liver metastasis after radical resection of colorectal cancer (P < 0.05). The prediction model of metachronous liver metastases after radical resection of colorectal cancer was established. The scores of peripheral nerve invasion, low differentiation, vascular invasion, longest tumor diameter ≥5 cm, stage T_3-4 and stage N_1-2 were 48, 68, 88, 60, 12 and 100, respectively. The total score of each factor corresponds to the probability of occurrence of metachronous liver metastasis. The area under the curve (AUC) of ROC curve was 0.768 (95%CI: 0.672-0.864). The calibration curve showed that the probability of metachronous liver metastasis predicted by the graph model after radical resection of colorectal cancer was in good agreement with the actual probability (P > 0.05).

Peripheral nerve invasion, low differentiation, vascular invasion, longest tumor diameter ≥5 cm, stage T_3-4, and stage N_1-2 are all independent risk factors for the occurrence of metachronous liver metastases after radical resection of colorectal cancer.