Clinical Impact of Inferior Mesenteric Lymph Node Metastasis in Patients with Cancer of the Sigmoid Colon or Rectum

The aim of this study was to clarify the clinical impact of inferior mesenteric lymph node (IMLN) metastasis from cancer of the sigmoid colon or rectum. A total of 952 patients underwent curative surgery with IMLN dissection for either sigmoid colon cancer or rectal cancer from January 2000 to August 2018. Of these, 26 (2.7%) were pathologically diagnosed with IMLN metastasis. Excluding 1 patient, 25 patients were retrospectively investigated for clinicopathological characteristics and long-term outcomes. Specifically, the clinical course of patients with recurrence was meticulously scrutinised. Of the 25 patients, 14 (56%) had recurrence during the follow-up period. The 5-year recurrence-free survival was 31.2%, and 5-year overall survival was 59.7%. No serious morbidity, such as anastomotic leakage, was observed. Of the 14 patients with recurrence, 6 underwent secondary surgery with curative intent and 5 of the 6 patients remained cancer-free. In contrast, 8 patients were treated with chemotherapy, radiotherapy or best supportive care. Although IMLN metastasis was strongly associated with recurrence, long-term survival could be expected in most cases. Furthermore, there could be a chance for complete cure in patients with recurrence if secondary surgery is successfully carried out.