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: chi(2)=69.06, P<0.0001) and disease-free survival (log-rank: chi(2)=69.06, P<0.0001) between the two groups. Furthermore, there were significant differences in overall survival (log-rank: chi(2)=18.47, P<0.0001) and disease-free survival (log-rank: chi(2)=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.