Oncologic Impact of Extracapsular Invasion of Nodal Metastasis in Patients with Stage III Rectal Cancer

ABSTRACT

PURPOSE: Extracapsular invasion (ECI) of nodal metastasis is reported to be a prognosticator of colorectal cancer. However, limited knowledge exists about the prognostic value of ECI in stage III rectal cancer. METHODS: From January 1996 to June 2004, 202 stage III rectal cancer patients who underwent surgery were enrolled in this study. The patients were divided into two groups according to ECI (patients with ECI, ECIP, n=122; patients without ECI, ECIN, n=80). The potential prognostic factors were compared in a Cox model. RESULTS: Of 916 positive nodes examined, ECI was seen in 46.7% of the positive nodes. The univariate comparison between the two groups revealed the five-year results after a median follow-up of 48.0 mo. The local control rate of ECIP did not show a significant difference from that of ECIN (77.0% vs. 85.4%, P=0.550). The disease-free survival rate and the overall survival rate differed for the two groups, with rates of 44.1% and 50.0% for ECIP and 70.4% and 63.2% for ECIN (P<0.001, P=0.049, respectively). The impact of ECI on the disease-free survival was confirmed in a Cox model. In a subgroup analysis, no significant differences in the recurrence and the survival rates were seen between the N1 ECIP and the N2 ECIN subgroups. CONCLUSION: Although ECI is not a risk factor for survival and local relapse, ECI is a prognosticator of overall recurrence. Based on these findings, more aggressive adjuvant treatment seems to be needed for decreasing the overall recurrence in stage III rectal cancer with ECI.