Background: Our aim was to evaluate the usefulness of serum amyloid A (SAA) measurements in comparison with C-reactive protein (CRP) in the early prediction of infectious complications among patients undergoing laparoscopic surgery for colorectal cancer Methods: Consecutive patients undergoing laparoscopic resection for colorectal cancer were analyzed prospectively. All subjects had the Enhanced Recovery After Surgery protocol implemented. Blood samples were taken from all patients and SAA and CRP were measured on the day of surgery and on the three consecutive post-operative days (PODs). Patients were divided into two groups (Group 1 without complications, Group 2 with complications), and these groups were compared.
Results: The study included 81 patients (61 in Group 1 and 20 in Group 2). Starting from POD2, significant differences between the groups were observed for both SAA and CRP. On POD2, the median CRP values were 116.7 mg/L and 256.9 mg/L in Groups 1 and 2, respectively (p = 0.00002). On POD3, the median SAA concentration was 445 mg/L in Group 1 and 1,412 mg/L in Group 2 (p = 0.00003). The CRP concentrations were 80.2 mg/L and 247.1 mg/L in Groups 1 and 2, respectively (p = 0.00001). A receiver operating characteristic (ROC) curve analysis showed that measurements of POD3 had the highest specificity and sensitivity with no significant differences between CRP and SAA (on POD3 for SAA sensitivity 83.3% and specificity 94%; for CRP: sensitivity 88% and specificity 86%).
Conclusion: Measurements of SAA are useful in predicting infectious complications even on the early post-operative days. It has characteristics similar to CRP, and its best values are reached on POD3.
Keywords: colorectal cancer; laparoscopic surgery; post-operative complications; serum amyloid A.