Prognostic value of apical lymph node metastasis at the inferior mesenteric artery in sigmoid and rectal cancer patients who undergo laparoscopic surgery.

Background and objectives Evidence supporting the importance of apical lymph nodes (LNs) and the potential long-term impact of LN metastases at the inferior mesenteric artery (IMA) lymphectomy remains limited. This study aimed to evaluate the prognostic value of LNs at the IMA (IMA-LN) in sigmoid and rectal cancer patients undergoing laparoscopic surgery. Methods We retrospectively evaluated 265 consecutive patients who underwent laparoscopic sigmoid or rectal cancer surgery between August 2016 and May 2020. They were divided into two groups according to the pathological results of the IMA LNs: IMA-LN negative (n = 248) and IMA-LN positive (n = 17). Results The IMA-LN negative group had significantly better overall survival (OS) (p = .020) and disease-free survival (DFS) (p = .000) than did the IMA-LN positive group. IMA-LN metastasis was associated with worse OS and DFS regardless of the pN stage. Patients with IMA-LN metastasis had a higher risk of postoperative recurrence, especially liver (p = .000) and lung (p = .025) metastasis, than did those without metastasis. However, there was no significant difference in the local recurrence rate between the two groups. Conclusions IMA-LN metastasis is an independent risk factor for poor prognosis in sigmoid and rectal cancer. Dissecting and evaluating IMA-LN separately is a more accurate and practical method for predicting prognosis.