IMPROVEMENT IN REDOX HOMEOSTASIS AFTER CYTOREDUCTIVE SURGERY IN COLORECTAL ADENOCARCINOMA

Abstract

colorectal cancer (CRC) as one the most common cancer type is associated with oxidative stress. Surgery is the only curative modality for early-stage CRC. The aim of this study was to evaluate the oxidative damage biomarkers as well as enzymatic and nonenzymatic antioxidants in patients with CRC before and after tumor resection in healthy controls. 60 patients with stage I/II colorectaL adenocarcinoma and 43 healthy controls were recruited in this study. We measured plasma levels of oxidative damage biomarkers, including advanced oxidation protein products (AOPP), advanced glycation end products (AGEs), malondialdehyde (MDA), and oxized low-density lipoprotein (ox-LDL) at baseline and after tumor removal. We also evaluated the plasma activuty of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) as enzymatic antioxidants and the ferric reducing antioxidants power (FRAP) assay for nonenzymatic antioxidant capacity. Patients with CRC had significantly higher AGE, AOPP, MDA, and ox-LDL and also FRAP levels and higher SOD and GPx and lower CAT activity levels compared to healthy controls (p<0,05). We did not observe any statistically significant correlation between redox biomarkers and the size and stage of tumor. AGEs (72,49 +/- 7.7 vs. 67.93 +/- 8.8, p< 0,001), AOPP (137.64 +/- 21.9 vs. 119.08 +/- 33.1 p<0,001), MDA (3.56 +/- 0.30 vs. 3.05 +/- 0.33 p< 0,001), and ox-LDL (19.78 +/- 0.97 vs. 16.94 +/- 1.02, p< 0,001) concentrations reduced significantly after tumor removal. The largest effect sizes were found in ox-LDL (d = - 2.853, 95% CI 2.50 - 3.19) and MDA (d = - 0.43 - 0.57). Serum FRAP lelvels (1097.5 +/-156.7 vs. 1239.3 +/- 290, p< 0,001) and CAT (2.34 +/- 0.34 vs. 2.63 +/- 0.38, p< 0,001), GPx (102.37 +/- 6.58 vs. 108.03 +/- 6.95, p< 0,001), and SOD (5.13 +/- 0.39 vs. 5.53 +/- 0,31 p< 0,001) activity levels increased significantly after surgery. The largest effect sizes among antioxidants were seen in SOD (d = 1.135, 95% CI 0.46 - 0.34) and GPx (d = 0.836, 95% CI 0.35 - 0.23>). This study indicated that patients with colorectal cancer high higher levels of oxidative stress and antioxidants activity compared to healthy controls. After surgical resection of tumor, we observed a substantial improvement in redox homeostasis.