Therapeutic significance of residual metastatic inferior mesenteric artery nodes in stage II/III low rectal cancer after neoadjuvant therapy: multicentre analysis

There is currently no consensus on routine inferior mesenteric artery node (IMAN) dissection for rectal cancer, as evidence that high ligation (HL) improves survival remains inconclusive; indeed, IMAN metastasis is uncommon, so the oncological benefit of routine HL is limited. Notably, IMAN dissection remains standard in China and carries legal weight under current national guidelines1. Although neoadjuvant chemoradiotherapy (CRT) is standard for locally advanced rectal cancer, the risk of IMAN involvement in clinical stage II/III low tumours after neoadjuvant CRT is poorly defined. Published rates (0.3–13.9%) come from retrospective, non-randomized studies subject to selection bias, mixing colon and rectal tumours, and with inconsistent CRT use2–4; prospective data are also lacking5. Therefore, the aim of this study was to analyse a prospective, multicentre cohort of patients with clinical stage II/III low rectal cancer, who were uniformly treated with long-course CRT plus total mesorectal excision (TME), to determine the incidence, predictors, and prognostic impact of IMAN metastasis.