The prognostic role of fasting plasma glucose levels on survival in advanced colorectal cancer patients with type II diabetes mellitus: a retrospective cohort study

BACKGROUND: Previous studies have shown that type II diabetes mellitus (T2DM) has a significant effect on the occurrence and development of colorectal cancer (CRC). The associations between fasting plasma glucose (FPG) and overall survival (OS) of CRC patients with T2DM are still controversial. The present study sought to examine the association between FPG control and OS in advanced CRC patients with T2DM. METHODS: The data of advanced CRC patients with T2DM who were admitted to Harbin Medical University Cancer Hospital from May 2010 to May 2019 were retrospectively collected and examined. Record patient clinical data including age, sex, blood pressure, body mass index (BMI), primary tumor site, T stage, N stage, histological grade, number of metastatic sites, primary tumor surgery, etc. The baseline FPG which was measured before the first-line treatment and the FPG measured before each admission treatment during advanced chemotherapy were collected. OS was determined as the end point of the study. All the patients were followed-up for at least 3 years. The Kaplan-Meier log-rank method and the Cox proportional hazards regression analyses were used for the analysis of OS and hazard factors. RESULTS: A total of 210 patients met the inclusion criteria for the study, who had a median age of 66.5 years; 94 patients had baseline FPG levels ≤7 mmol/L, and 116 patients had baseline FPG levels >7 mmol/L. Compared to the baseline FPG >7 mmol/L group, the OS of patients in the baseline FPG ≤7 mmol/L group was not significantly prolonged (P=0.88). There were 52 patients in the FPG-A group and 61 in the FPG-B group. Similarly, there was no significant difference in OS between the FPG-A and FPG-B groups (P=0.96). The N0 stage subgroup analysis showed that glycemic control ≤7 mmol/L resulted in longer OS. CONCLUSIONS: The results of the present study showed that FPG levels may not affect the survival of advanced CRC patients with T2DM. However, this needs multicenter prospective studies to confirm.