Prognostic value of glycated hemoglobin in colorectal cancer

Aim: To investigate the clinical significance of routinely used glycemic parameters in a cohort of colorectal cancer (CRC) patients. Methods: Pre-treatment fasting blood glucose, insulin, HbA1c and homeostasis model of risk assessment (HOMA-IR) were retrospectively evaluated in a case-control study of 224 CRC and 112 control subjects matched for sex, obesity and diabetes frequency and blood lipid profile. Furthermore, the prognostic value of routinely used glycemic parameters towards progression-free (PFS) and overall survival (OS) was prospectively evaluated. Results: Fasting blood glucose, insulin, HOMA-IR and HbA_1c (all P < 0.0001) levels were higher in non-diabetic CRC patients compared with obesity-matched controls. All parameters were associated with increased CRC risk at ROC analysis, but no relationship with clinical-pathological variables or survival outcomes was observed for glycemia, insulinemia or HOMA-IR. Conversely, advanced CRC stage (P = 0.018) was an independent predictor of increased HbA1c levels, which were also higher in patients who had disease progression compared with those who did not (P = 0.05). Elevated HbA1c levels showed a negative prognostic value both in terms of PFS (HR = 1.24) and OS (HR = 1.36) after adjustment for major confounders, which was further confirmed in a subgroup analysis performed after exclusion of diabetic patients. Conclusion: HbA1c might have a negative prognostic value in CRC, thus suggesting that glycemic metabolic markers should be carefully monitored in these patients, independently of overt diabetes.