Preoperative and Postoperative C-Reactive Protein to Albumin Ratio (CAR) as a Prognostic Marker for Survival of Esophageal Squamous Cell Carcinoma Patients After Surgery

Background/Aim: Recent studies have reported that the C-reactive protein (CRP) to albumin ratio (CAR) may be a useful prognostic biomarker in various types of cancer patients. However, the mechanism underlying this observation is unclear. The present study aimed to clarify why the CAR can predict post-esophagectomy prognosis, the relationship between pre- and postoperative CAR, and whether postoperative CAR can predict the prognosis of esophageal cancer patients. Patients and Methods: We investigated 158 esophagectomy patients with esophageal squamous cell carcinoma. Hematological examinations were performed on postoperative days (POD) 1, 3, 5, 7, 10, and 14. Results: Preoperative CAR was a significant independent prognostic factor of overall survival (OS) [hazard ratio (HR)=2.247; p=0.0005], and there was a strong correlation between preoperative CAR and tumor depth. The preoperative high-CAR (pre-high-CAR) group had significantly higher CAR on all postoperative days (POD). We then divided the patients as follows: those with at least two low-CAR days on POD 5, 7, and 10 were assigned to the modified post-low-CAR (mPost-low-CAR) group, and others were assigned to the modified post-high-CAR (mPost-high-CAR) group. The 5-year OS rate was significantly higher in the mPost-low-CAR group than in the mPost-high-CAR group, which predicted a more accurate prognosis (p<0.0001, HR=2.769). Conclusion: Preoperative CAR was associated with tumor depth and diameter, and patients in the pre-high-CAR group continued to have significantly higher CAR postoperatively. These factors were presumed to reflect disease prognosis. Furthermore, grouping by CAR on POD 5, 7, and 10 reflected patient prognosis more accurately than preoperative CAR.