Hypothesis: Nowadays, rectal cancer is an important healthcare challenge that affects many thousands of people each year worldwide, being diagnosed especially after the age of 50 years. Objective: This study attempted to evaluate the oxidative stress in patients with rectal cancer. Methods and results: 30 patients from the "Prof. Dr. Al. Trestioreanu" Institute of Oncology in Bucharest were treated with neoadjuvant radiochemotherapy during 2014 and 2016 and were included in the clinical study. Blood samples were obtained in dynamics during the treatment. From the blood samples, the serum was separated and used to identify the biochemical oxidative stress parameters. Results: Regarding the determination of lipid peroxides, albumin thiols, the cuprum oxidase activity of ceruloplasmin, the values registered in the dynamic of the treatment highlighted their increase to a maximum at the treatment's endpoint due to an important oxidative stress. Regarding the serum values for total antioxidants, the results pointed out the activation of the natural protection systems, which in time were overwhelmed, due to the installed oxidative stress. Conclusion: Part of the cytotoxic effect of radiotherapy was due to the production of oxidative stress. The cell was constantly exposed to the cytotoxic action of the reactive oxygen species. The obtained results indicated the dual relation to which the tumoral cell exposed itself and the installed oxidative stress, respectively, the oxidative stress being a cause or a consequence of the malign transformation. Abbreviations: CT = computed tomography, MRI = magnetic resonance imaging, ESMO = European Society for Medical Oncology, ECOG = performance status scale.
Keywords: oxidative stress; radiotherapy; rectal cancer.