Abstract:Objective To investigate the relationship between type 2 diabetes mellitus (T2DM) and lymph node metastasis in patients with colorectal cancer. Methods A total of 1 624 patients with colorectal cancer in the First Affiliated Hospital of Chongqing Medical University from January 2016 to July 2017 were collected for a retrospective case-control study,in order to analyze the lymph node metastasis of patients with T2DM (n=208) and non-T2DM (n=1 416).The statistical test standard was α=0.05.When the partitioning chi-squared test of R×C table was used,the test standard was adjusted to α ′=0.017. Results There were 638 cases of lymph node metastasis,96 cases in the T2DM group and 542 cases in the non-T2DM group.The lymph node metastasis rate in the T2DM group was higher than that in the non- T2DM group (46.2% vs 38.3%,P=0.030).In the T2DM group(n=208),there were 152 patients with medium and long-term T2DM (course of T2DM >2 years),56 patients with short-term T2DM (course of T2DM≤2 years).The lymph node metastasis rate of long-term T2DM patients was higher than that of non-T2DM patients (48.7% vs 38.3%,P<0.017).The lymph node metastasis rate was 56.1% in T3-T4 T2DM patients (n=157),44.6% in T3-T4 non-T2DM patients (n=1 074),15.7% in T1-T2 T2DM patients (n=51),18.4% in T1-T2 non-T2DM patients (n=342).The lymph node metastasis rate was higher in T3-T4 T2DM patients than that in T1-T2 T2DM patients (P<0.017). Conclusions The risk of lymph node metastasis is higher in patients with diabetes mellitus,especially in colorectal cancer with a diabetes course of more than 2 years.The risk of lymph node metastasis in colorectal cancer patients with high T stage is higher,but it has not been shown a statistically significant impact of diabete on the lymph node metastasis rate in different T stage patients,which needs further study.