Objective To investigate the risk factors associated with lymph node metastasis of T1 and T2 rectal cancer. Methods Clinicopathological data of 576 patients with stage T1 to T2 rectal cancer without serosal invasion confirmed by pathology undergoing curative resection in Changhai Hospital from January 1999 to December 2013 were analyzed retrospectively. The relationship of clinicopathological factors of overall patients and stage T1 patients with lymph node metastasis was analyzed by univariate or multivariate analysis. Results The lymph node metastasis rate of stage T2 rectal cancer was significantly higher than that of stage T1 [22.9% ﹙108/463) vs. 9.7%﹙11/113), P=0.002], and the difference of stage T2a and T2b was not significant [22.0%﹙38/173) vs. 23.4%﹙68/290), P=0.733]. Multivariate analysis showed that poor differentiation﹙HR=1.54, 95% CI:1.12 to 2.13), abnormal carbohydrate antigen ﹙CA) 199 level ﹙HR=2.05, 95% CI:1.16 to 3.62), ulcerative mass ﹙HR=1.58, 95% CI:1.05 to 2.39) and invasion of muscle ﹙of inner ring muscle HR=3.55, 95%CI:1.79 to 7.02; of outer longitudinal muscle, HR=2.35, 95% CI:1.21 to 4.60) were independent risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer﹙all P<0.05). Meanwhile poor differentiation ﹙HR=4.43, 95% CI:1.51 to 13.03), abnormal carcinoembryonic antigen ﹙CEA) level﹙HR=4.66, 95% CI:1.18 to 20.11) and ulcerative mass ﹙HR=6.23, 95% CI:1.51 to 25.66) were risk factors of lymph node metastasis in patients with stage T1 rectal cancer. Conclusion Poor differentiation, preoperative high CA199, ulcerated tumor, invasion of inner ring muscle or outer longitudinal muscle are risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer, while the invasion depth of muscularis propria is not risk factor. Besides, poor differentiation, abnormal CEA level, ulcerated tumor are risk factors of lymph node metastasis in stage T1 rectal cancer patients, which can be used as reference for local excision in patients with stage T1 rectal cancer.

Objective To investigate the risk factors associated with lymph node metastasis of T1 and T2 rectal cancer. Methods Clinicopathological data of 576 patients with stage T1 to T2 rectal cancer without serosal invasion confirmed by pathology undergoing curative resection in Changhai Hospital from January 1999 to December 2013 were analyzed retrospectively. The relationship of clinicopathological factors of overall patients and stage T1 patients with lymph node metastasis was analyzed by univariate or multivariate analysis. Results The lymph node metastasis rate of stage T2 rectal cancer was significantly higher than that of stage T1 [22.9% ﹙108/463) vs. 9.7%﹙11/113), P=0.002], and the difference of stage T2a and T2b was not significant [22.0%﹙38/173) vs. 23.4%﹙68/290), P=0.733]. Multivariate analysis showed that poor differentiation﹙HR=1.54, 95% CI:1.12 to 2.13), abnormal carbohydrate antigen ﹙CA) 199 level ﹙HR=2.05, 95% CI:1.16 to 3.62), ulcerative mass ﹙HR=1.58, 95% CI:1.05 to 2.39) and invasion of muscle ﹙of inner ring muscle HR=3.55, 95%CI:1.79 to 7.02; of outer longitudinal muscle, HR=2.35, 95% CI:1.21 to 4.60) were independent risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer﹙all P<0.05). Meanwhile poor differentiation ﹙HR=4.43, 95% CI:1.51 to 13.03), abnormal carcinoembryonic antigen ﹙CEA) level﹙HR=4.66, 95% CI:1.18 to 20.11) and ulcerative mass ﹙HR=6.23, 95% CI:1.51 to 25.66) were risk factors of lymph node metastasis in patients with stage T1 rectal cancer. Conclusion Poor differentiation, preoperative high CA199, ulcerated tumor, invasion of inner ring muscle or outer longitudinal muscle are risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer, while the invasion depth of muscularis propria is not risk factor. Besides, poor differentiation, abnormal CEA level, ulcerated tumor are risk factors of lymph node metastasis in stage T1 rectal cancer patients, which can be used as reference for local excision in patients with stage T1 rectal cancer.