Effects of major solid cancer surgery on oxidative stress assessed by plasma xanthine oxidase and adenosine deaminase activity : a pilot study.

Solid cancers and their surgical treatment are both major sources of oxidative stress (OS), which contributes to adverse clinical outcomes. This study aimed to explore the impact of major solid cancer surgery on plasma OS concentrations by assessing key biomarkers. We conducted an exploratory, prospective study including 36 patients undergoing elective major cancer surgery. Pre- and postoperative plasma concentrations of adenosine deaminase (ADA), xanthine oxidase (XO), ischemia-modified albumin (IMA), redox potential (RP), and high-sensitivity troponin T (hs-TnT) were measured. Thirty matched healthy controls were used for comparison. Preoperative plasma concentrations of ADA, XO, IMA, and RP were significantly elevated in patients, as compared to controls, indicating high baseline oxidative stress. Postoperatively, plasma concentrations of XO, IMA, and RP decreased significantly (p < 0.05) but remained higher than those of controls, while ADA concentrations showed no significant postoperative decrease. The plasma concentration of hs-TnT increased modestly but significantly after surgery (p = 0.003). A negative correlation between preoperative ADA and XO concentration was observed (r = -0.46; p = 0.006). Solid cancers were associated with elevated plasma expression of OS, which significantly decreased after surgery. However, major surgery itself induces a residual oxidative burden, reflected by an elevation in myocardial biomarkers. The increased levels of OS levels before surgery could fit the cancer-driven "priming/second-hit" framework. The negative correlation between ADA and XO suggests a potential feedback mechanism. These findings bring new insights regarding OS modulation during major solid cancer surgery and warrant further investigation in larger studies.