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, Hb A1 c 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 Hb A1 c levels, which were also higher in patients who had disease progression compared with those who did not(P = 0.05). Elevated Hb A1 c 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 HbA 1c 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.