Cardiovascular assessment of oncological patients suggests that cancer can lead to subclinical damage of the heart. The aim of the present study was to analyze the value of baseline cardiovascular biomarkers in patients with newly diagnosed colon cancer prior to treatment. Additionally, another aim was to establish baseline cut-off alert values for this low-intensity neoplastic damage. A total of 51 patients with newly diagnosed colon cancer, without history of cardiac disease, were enrolled in a prospective, cross-sectional study. All patients underwent clinical, biochemical and basic echocardiographic evaluation before starting treatment. Patients were assessed for myocardial damage using high-sensitivity troponin T (hs-TnT), creatine kinase-MB (CK-MB) and N-terminal-pro B-type natriuretic peptide (NT-proBNP). A group of 28 healthy controls was included for comparison. Cardiac ultrasound revealed similar left ventricular (LV) ejection fraction but enlarged LV chambers compared with the control group (LV at end systole, 29.50 vs. 26.00 mm; LV at end diastole, 44.50 vs. 38.00 mm; P<0.001 in both cases). The levels of cardiovascular biomarkers of myocardial damage were higher in the patients than in the control group (CK-MB, 17.00 vs. 11.00 IU/l, P<0.001; hs-TnT, 8.20 vs. 3.00 ng/l, P<0.001; 155.40 vs. 48.50 pg/ml, P=0.001). In multivariate analysis, CK-MB and hs-TnT retained statistical significance (P= 0.004 and P= 0.045, respectively). Moreover, it was demonstrated that new cut-offs for hs-TnT (8.00 ng/l) and NT-proBNP (220.00 pg/ml) can identify cardiac damage in patients ≥65 years old. Thus, the present study confirmed the hypothesis that a basic cardiovascular assessment of treatment-naïve patients with colon cancer can identify important pre-treatment myocardial impact. Adapted cut-off values should be set for cardiovascular biomarkers in the cancer population, different from those currently accepted for acute coronary syndromes or heart failure.