Preoperative oxidative stress as a biomarker of postoperative complications in colorectal cancer patients

Introduction
Relationships between redox homeostasis, nutritional status, and postoperative complications in patients with colorectal cancer are still unexplained.

Aim
This study aimed to evaluate selected parameters of oxidative stress and nutritional status in colorectal cancer patients and their impact on postoperative complications.

Material and methods
The study included 50 patients with colorectal cancer. In all patients, body mass index (BMI), body weight loss, and the Nutritional Risk Screening tool (NRS 2002) were assessed. The levels of total protein and albumin, complete blood count (CBC), total antioxidant capacity (TAC), total oxidant status (TOS), and malondialdehyde (MDA) level were measured. Oxidative stress index (OSI) and the TAC/MDA ratio were calculated. 

Results
We detected a significantly higher TAC level (p = 0.0017) and lower TOS level in patients with normal BMI compared to those with increased BMI. We observed a higher TAC level in patients without weight loss (p = 0.0407), whereas the MDA concentration was higher in patients with weight loss than in those without weight loss (p = 0.0025). TAC was significantly higher whereas TOS, OSI, and TAC/MDA ratio were significantly lower in patients without symptoms of malnutrition (p < 0.05). Patients without postoperative complications had higher levels of TOS and MDA, and a lower level of TAC (p < 0.05). 

Conclusions
The occurrence of postoperative complications may be associated with increased oxidative stress in patients with colorectal cancer.