Distribution of Lymph Nodes in Stage III Patients With Mid and Low Rectal Cancer: Preliminary Study

PURPOSE: Most patients with rectal cancer undergo a total mesorectal excision and a partial resection of the sigmoid colon to improve oncologic outcomes. The aim of this study was to assess the distribution of lymph nodes (LNs) in rectal cancer. METHODS: The records of 54 patients with mid and low rectal cancer between April 2015 and March 2017 were reviewed, and 49 patients were enrolled in this study. All harvested LNs were analyzed according to the harvested area: the mesorectum area (MA), the vascular pedicle area (VA), and the sigmoid area (SA). RESULTS: Finally, 865 LNs were harvested from all patients, and of these, 71 (8.2%) showed metastases. In stage III patients, 343 LNs were harvested, and of these, 52 (15.2%) showed metastases. Significant differences were found in the total numbers of harvested LNs by area (P < 0.001) and in the numbers of harvested positive LNs by area (P < 0.001). In stage III patients, LNs from the MA were more frequently to be positive than were those from the VA (P < 0.001) or the SA (P < 0.001). CONCLUSION: LN metastasis in the SA was rare. Therefore, resecting the mesorectum and the vascular pedicle may be more important than resecting the sigmoid mesentery due to concerns about LN metastases.