C-Reactive Protein (CRP)/Albumin Ratio (CAR) pre-treatment as a predictive factor of radiological response after neoadjuvant chemotherapy in Locally Advanced Rectal Cancer (LARC) patients at Dr. Soetomo General Hospital, Surabaya, Indonesia

Background: Several serum inflammatory markers have been investigated as prognostic biomarkers for rectal cancer patients, including C-Reactive Protein (CRP)/Albumin Ratio (CAR). We aimed to examine the association between the CAR pre-therapy value and radiological response after neoadjuvant chemotherapy. Methods: We recruited locally advanced rectal cancer patients who underwent FOLFOX first-line neoadjuvant chemotherapy (NAC) at Dr. Soetomo General Hospital (Surabaya, Indonesia) from January 2015 to December 2020. Before neoadjuvant chemotherapy treatment, the C-reactive protein (CRP) and albumin were measured. The chemotherapy response was performed by evaluating the CT scan result before and after the NAC was given. We used RESIST criteria to assess the radiological response after NAC treatment. Data were analyzed using SPSS version 23 for Windows. Results: We included a total of 102 patients, with the female being the predominant gender with LARC (52%.0). The well differentiated adenocarcinoma was the most common adenocarcinoma type found in this study (59.8%). We found 57 patients with positive responses and 45 patients with negative responses. Patients with well-differentiated status who had adenocarcinoma had a higher chance to have a positive response to NAC. Patients with low CAR values had a 2.13 times higher chance of having a positive chemotherapy response than patients with high CAR values (95% CI = 1.30-3.30). Conclusion: There was a significant relationship between high CAR values and poor radiological response after neoadjuvant chemotherapy in locally advanced rectal cancer patients. The CAR value may be a potential biomarker to predict the radiologic response after NAC treatment.