Diabetic severity and oncological outcomes of colorectal cancer following curative resection: A population-based cohort study in Taiwan

Abstract

Background: Although diabetes is a poor prognostic factor for colorectal cancer (CRC), whether diabetes severity provides an additional predictive value for CRC prognosis remains unclear. The study aimed to investigate the prognostic differences after curative CRC resection among patients with different diabetic severities.

Methods: This population-based retrospective cohort study analyzed data registered between 2007 and 2015 in the Cancer Registry Database, which is linked to the National Health Insurance Research Database and National Death Registry. Patients with CRC who underwent curative radical resection for stage I-III disease were evaluated, with their diabetic status subdivided into no diabetes, diabetes without complication, and diabetes with complications. Cox regressions were applied to determine the association between diabetes severity and CRC survival, including overall survival (OS), disease-free survival (DFS), time to recurrence, and cancer-specific survival (CSS).

Results: A total of 59,202 patients with CRC were included. Compared with the no diabetes group, the diabetes without complication group has insignificantly worse OS (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01-1.09), DFS (HR, 1.08; 95% CI, 1.04-1.12), and CSS (HR, 0.98; 95% CI, 0.93-1.03), whereas those with complicated diabetes had a significantly higher risk of poor survival (OS: HR, 1.85; 95% CI, 1.78-1.92; DFS: HR, 1.75; 95% CI, 1.69-1.82; CSS: HR, 1.41; 95% CI, 1.33-1.49). Patients with CRC and diabetes also had a higher risk of recurrence than did those without diabetes. Sex and TNM staging were important effect modifiers.

Conclusions: Among patients with CRC who undergo curative resection, the severity of the diabetes is inversely correlated with long-term outcomes, especially in women and patients in the earlier stages of CRC.

Plain language summary: The prognostic impact of diabetes severity in colorectal cancer (CRC) is yet to be clarified. In this cohort study of 59,202 patients with CRC, compared with patients with CRC and without diabetes, those with uncomplicated diabetes had an insignificantly worse CRC survival, whereas those with complicated diabetes had a significantly higher risk of poor survival. Multidisciplinary medical care to prevent progression into diabetes with complications is needed to improve survival among patients with CRC and diabetes.

Keywords: colorectal cancer; diabetes mellitus; diabetes with complication; disease-free survival; overall survival.