The usefulness of the status of extranodal tumor extension as a factor that can predict the recurrence of stage III colorectal cancer.

Background: Extranodal tumor extension (ENTE) is considered a poor prognostic factor in colorectal cancer (CRC). This study aimed to investigate the risk factors for recurrence according to ENTE status in stage III CRC. Methods: We retrospectively evaluated 169 consecutive stage III CRC patients. All patients underwent a curative resection between 2005 and 2010. The presence or absence of ENTE was assessed in the resected lymph nodes. Results: ENTE was observed in 65 (38.5%). Recurrence occurred in 38 patients (22.5%) and was more frequent (p = .041) in the ENTE (+) group. Disease-free survival (p = .016) was significantly shorter in the ENTE (+) group than in the ENTE (-) group. In a univariable analysis, recurrence was associated with vascular invasion (p = .006), perforation (p = .024) in the ENTE (-) group and perforation (p = .048) in the ENTE (+) group. In a Cox's regression test, vascular invasion (p = .014) and the higher ratio of metastatic lymph nodes/total removed lymph nodes (MLN/TLN) (0.009) in the ENTE (-) group and perforation (p = .025) in the ENTE (+) group were independent risk factors of recurrence. Conclusions: Vascular invasion and the higher ratio of MLN/TLN in ENTE (-) patients and perforation in ENTE (+) patients were independent risk factors of recurrence.