Risk factor analysis for radiographic para-aortic lymph nodes metastasis in left-sided colorectal cancer：a retrospective study

Background: Synchronous para-aortic lymph node (PALN) metastasis from colorectal cancer (CRC) is rare, and the positive predictive value of pre-operative CT was low. This study aimed to clarify risk factors radiographic PALN metastasis in left-sided CRC for improving the accuracy of pre-operative CT scan. Patients and Methods: Patients with pathologically and radiographically confirmed diagnosis of left-sided CRC were enrolled between January 2019 and August 2021. The Correlations between clinicopathologic data and radiographic PALN metastasis were analyzed chi-squared test or Fisher exact test and the multivariate binary logistic regression model was used for multivariate analyses. Results There were 15(3.56%) patients with radiographic PALN metastasis. The hepatic (P = 0.023) and inferior mesenteric lymph nodes (IMLN) (P < 0.001) metastases, elevated serum carcinoembryonic antigen (CEA) (P = 0.007) and carbohydrate antigen19-9 (CA19-9) (P = 0.021) levels, longer tumor length (P = 0.003), lower degree of tumor differentiation (P < 0.001), deeper tumor invasion (P = 0.038), later lymph node staging (P < 0.001), perineural invasion (P = 0.009) and lymphovascular involvement (P < 0.001) were the risk factors for radiographic PALN metastasis. Among them, the radiographic IMLN metastasis (P = 0.003, OR = 20.927, 95% CI 2.823–155.820) was the only independent risk factor. Conclusion Some clinicopathologic characteristics, especially IMLN metastasis, are the risk factors for PALN metastasis.