Metastatic potential in T1 and T2 colorectal cancer

Survival of patients with colorectal cancer confined to the muscularis propria (stage I) is excellent after curative resection. However, some patients are likely to develop lymph node and distant metastasis that can ultimately cause death. The purpose of this study was to identify the possible predictors of lymph node and distant metastasis in T1 and T2 colorectal cancers.

In total 208 patients with T1 and T2 colorectal cancers who underwent surgical resection in Taipei Veterans General Hospital from July 1996 to December 2001 were enrolled. The clinicopathological variables including age, gender, tumor location (rectum/colon), preoperative carcinoembryonic antibody level, depth of tumor invasion, lymphovascular invasion, and unfavored histology corresponding to the metastasis assessed pathologically were analyzed. Categorical variables were analyzed using Chi-square with Yates' correction. The independent predictor of lymph node and distant metastasis was determined with multivariate binary logistic regression.

Of the 208 T1 and T2 colorectal cancer patients, 36 (17.3%) had lymph node metastasis and 5 (2.4%) had distant metastasis at surgery. The risk of lymph node metastasis was 14.3% (8/56) in T1 and 18.4% (28/52) in T2 colorectal cancer. The tumors with evidence of lymphovascular invasion had a significantly higher incidence of lymph node metastasis than those without lymphovascular invasion (43.6% vs. 9.4%; p<0.001). The independent risk factor for lymph node metastasis was lymphovascular invasion only (95% confidence interval, 3.37-19.97; p<0.001), whereas that for distant metastasis was preoperative carcinoembryonic antibody level >5ng/mL only (95% confidence interval, 0.03-0.21; p<0.001). The negative predictive value of possible adverse risk factors including preoperative carcinoembryonic antibody level >5ng/mL, lymphovascular invasion, and unfavored differentiation for metastasis was 93.5%.

Considering the negative predictive value of combined possible adverse risk factors, the risk of metastasis still was 6.5%. Therefore radical surgery was recommended for all T1 and T2 stage colorectal cancer patients except if the patient had a very high surgical risk.