Prognostic Impact of Extranodal Extension in Rectal Cancer Patients Undergoing Radical Resection Following Preoperative Chemoradiotherapy

Abstract Purpose Extranodal extension (ENE) of nodal metastasis has emerged as an important prognostic factor in many malignancies, including rectal cancer. However, its significance in patients with rectal cancer receiving preoperative chemoradiotherapy (PCRT) has not been extensively investigated. Thus, the aim of this study is to assess ENE and its prognostic impact in a large series of consecutive rectal cancer patients with lymph node metastasis following PCRT and curative resection. Methods Between January 2000 and December 2014, a total of 1,925 patients with rectal cancer underwent surgical resection following PCRT. Medical records of 469 patients with pathologic node positivity were reviewed retrospectively. Results Of the 469 patients, 118 (25.2%) presented with ENE. ENE was observed more frequently in those with advanced tumor stage (higher ypT, ypN, and ypStage), LVI, and PNI. Five-year disease-free survival (DFS) rate was lower in patients with ENE-positive tumors than those with ENE-negative tumors (36.1% vs. 52.3%, P = 0.003). Similarly, 5-year overall survival (OS) rate was lower in patients with ENE-positive tumors than those with ENE-negative tumors (60.2% vs. 70.6%, P Conclusions The presence of ENE in patients with rectal cancer undergoing PCRT is a negative prognostic factor, reflecting poor survival outcome.