OBJECTIVETo investigate the impact of tumor size on the prognosis of patients with colon cancer.

METHODSThe clinicopathologic factors of 345 cases who underwent curative surgery for colon cancer from January 2004 to June 2008 in the Peking University Cancer Hospital were analyzed retrospectively. The optimal cut-off value was determined by receiver-operator characteristic (ROC) analysis.

RESULTSThe overall 3-year survival rate was 85.1%. The optimal cut-off value was found to be 5.0 cm. The survival rate of patients with tumor size ≥5 cm and tumor size <5 cm was 79.5% and 90.5% respectively, and the difference was statistically significant(P=0.005). Multivariate analysis showed that preoperative CEA level (P=0.004), tumor size(P=0.020), regional lymph node metastasis(P=0.000), and lymphovascular invasion(P=0.002) were independent prognostic factors. Tumor size was significantly associated with overall survival in univariate and multivariate analyses in stage III( disease (P=0.011), but not in stage II( disease(P=0.827) using 5 cm as a cut-off.

CONCLUSIONSTumor size of 5 cm is an independent prognostic parameter for patients with stage III( colon cancer but not for stage II(. Determination of the association between tumor size and survival should be base on TNM staging.