Lymphovascular or Perineural Invasion May Predict Lymph Node Metastasis in Patients With T1 and T2 Colorectal Cancer

The aim of the study was to evaluate factors for predicting lymph node metastasis in patients who had T1 and T2 colorectal cancer. A total of 224 patients with T1 or T2 colorectal cancers who underwent radical surgery with regional lymphadenectomy from January 1999 to January 2008 were analyzed. Predictive factors for lymph node metastasis and prognostic factors were analyzed. Tumor stage was classified as T1 in 69 (30.8%) and T2 in 155 (69.2%) of patients. The overall incidence of lymph node metastasis was 21.0% (14.5% for T1 cancer and 23.9% for T2 cancer; P = 0.112). The node positive and negative groups were similar with regard to patient demographics, except that the former contained a significantly higher number of lymphovascular invasion and perineural invasion cases. During the median follow-up period of 49 months, the 5-year overall and disease-free survival rates for patients without lymph node metastasis were 97.1% and 94.6%, which were significantly higher than the rates for those with lymph node metastasis (85.5%, P = 0.008, and 82.0%, P = 0.007, respectively). A multivariate analysis revealed that lymph node status was the only significant independent prognostic factor for both overall survival (P = 0.025) and disease-free survival (P = 0.040). Moreover, the presence of lymphovascular invasion (P < 0.001) or perineural invasion (P = 0.004) was an independent predictor for lymph node metastasis. Lymph node metastasis was the most powerful predictor for poorer survival in patients with T1 or T2 colorectal cancer. For patients with positive lymphovascular or perineural invasion, radical surgery should be recommended because of a greater chance for lymph node metastasis.