Oncologic Outcomes of Colon Cancer Patients with Extraregional Lymph Node Metastasis: Comparison of Isolated Paraaortic Lymph Node Metastasis with Resectable Liver Metastasis

The treatment strategy and benefit of extended lymph node dissection among patients with preoperatively diagnosed paraaortic lymph node metastasis (PALNM) in colon cancer remains highly controversial. In the current study, we analyzed the oncologic outcomes of patients who underwent extraregional lymph node dissection for colon cancer with isolated PALNM. From March 2000 to December 2009, the study group included 1082 patients who underwent curative surgery for colonic adenocarcinoma with pathological lymph node metastasis. Of 1082 patients who underwent curative surgery for colonic carcinoma, 953 (88.1 %) patients underwent regional lymphadenectomy, and 129 (11.9 %) patients underwent paraaortic lymph node dissection. Pathologic examination revealed N1 stage disease in 738 (68.2 %), N2 in 295 (27.3 %), and PALNM in 49 (4.5 %). Five-year overall survival (OS) and disease-free survival (DFS) rate were significantly better in the regional LNM group than in the PALNM group (OS 75.1 vs. 33.9 %, p < 0.001; DFS 66.2 vs. 26.5 %, p < 0.001). Five-year OS and DFS were not significantly different between the PALNM and resectable liver metastasis patients who underwent curative resection (OS 33.9 vs. 38.7 %, p = 0.080; DFS 26.5 vs. 27.6 %, p = 0.604). PALNM in colon cancer is associated with poorer survival than regional lymph node metastasis and showed comparable survival rates with metastasectomy for liver metastasis. Further studies evaluating the net benefit of upfront chemotherapy compared with initial resection for patients with potentially resectable PALNM are needed.