Extended Lymph Node Dissection for Rectal Cancer with Radiologically Diagnosed Extramesenteric Lymph Node Metastasis

Abstract

The purpose of this study is to review the clinical outcomes of patients who received extended lymph node dissection for radiologically diagnosed extramesenteric lymph node metastasis. The authors reviewed clinical characteristics, short-term operative outcomes, and long-term oncologic outcomes of 151 patients who had received total mesorectal excision plus extended lymph node dissection for the treatment of radiologically diagnosed extramesenteric lymph node metastasis. The positive predictive value of the radiologic diagnosis of extramesenteric lymph node metastasis was 86.4% for lateral nodes and 40.0% for para-aortic nodes. It showed improvement over time. Perioperative mortality occurred in 3 patients (2.0%) and morbidity in 31 patients (20.5%). Pathologic examinations revealed metastatic para-aortic lymph nodes in 43 patients (PA) and metastatic lateral pelvic nodes in 36 patients (LP), while in 21 patients, metastasis was found in both (LP + PA). Both cancer-specific survival (CSS) and disease-free survival (DFS) were significantly different according to the extent of node metastasis (CSS: P < .001; DFS: P < .001) and univariate and multivariate analyses for prognostic factors revealed that the lymph node status as to location was the only factor. Patients with extramesenteric lymph node metastasis may be a distinct subgroup with poor prognosis. Extended lymph node dissection may have a role for those patients. However, the optimal treatment strategy remains inconclusive, for which further clinical research is necessary.