Prognostic value of inferior mesenteric artery lymph node metastasis in cancer of the descending colon, sigmoid colon and rectum.

AIM: This study aimed to analyse the potential significance of metastasis to the inferior mesenteric artery lymph node (IMA-LN) in patients with malignancy of the left colon and rectum. METHOD: A retrospective analysis of a cohort of 890 patients collected prospectively who underwent radical resection of a primary tumour of the descending colon, sigmoid colon and rectum in our department from 1 January 2009 to 31 December 2015 was performed. Patients were divided into an IMA-LN metastasis (IMA-LN (+)) group (n = 51) and a non IMA-LN metastasis (IMA-LN (-)) group (n = 839). A total of 801 patients were followed by a designated member of the study staff. Clinical features, pathological characteristics, recurrence patterns and survival rates were compared between the two groups. RESULTS: In the IMA-LN (+) group, the risk ratio of overall recurrence and tumour related death was 7.786 (95% CI 4.142-14.637) and 7.756 (95% CI 4.142-14.525) respectively. Significant differences were found in overall survival (log-rank: χ2  = 69.06, P < 0.0001) and disease-free survival (log-rank: χ2  = 69.06, P < 0.0001) between the two groups. Furthermore, there were significant differences in overall survival (log-rank: χ2  = 18.47, P < 0.0001) and disease-free survival (log-rank: χ2  = 16.99, P < 0.0001) between the IMA-LN (-) and IMA-LN (+) subgroups of patients with Stage N2 disease. Multivariate survival analysis indicated that IMA-LN (+) was an independent risk factor of poor prognosis. There was no difference in the prognosis between high tie and low tie with IMA-LN dissection. CONCLUSION: Inferior mesenteric artery lymph node metastasis was an independent predictive factor for high systemic recurrence. Low ligation of the IMA with IMA-LN dissection was not inferior to high ligation.