Evaluation of Salivary Oxidative Stress in Patients with Oral Squamous Cell Carcinoma Undergoing Head and Neck Radiotherapy

Introduction: Oral squamous cell carcinoma (OSCC) is one of the most common malignant neoplasms in the head and neck region. The standard therapeutic approach typically includes surgical intervention followed by adjuvant radiotherapy, which, although necessary, may significantly impair salivary gland function and disrupt redox homeostasis in the oral cavity.

Aim: The aim of this study was to evaluate the effect of radiotherapy on the quantity and quality of saliva, assessed through salivary biomarkers FRAS, MDA, and SOD, in patients with oral squamous cell carcinoma who had undergone surgical treatment and subsequent head and neck radiotherapy.

Materials and Methods: The study included 20 patients of both sexes, aged 41 to 76 years, who were surgically treated and subsequently underwent head and neck radiotherapy. Unstimulated saliva samples were collected at two time points: before and after completion of radiotherapy. Salivary flow rate was measured immediately after collection, and following sample processing, ferric reducing ability of saliva (FRAS), malondialdehyde (MDA) concentration, and superoxide dismutase (SOD) activity were determined spectrophotometrically.

Results: The salivary flow rate was significantly reduced after radiotherapy compared to the pre-treatment values. The post-radiotherapy FRAS levels were significantly lower, whereas MDA levels were significantly higher. SOD activity was slightly higher before radiotherapy compared to the post-radiotherapy values.

Conclusion: Our findings confirm that radiotherapy is associated with increased oxidative stress and reduced antioxidant capacity in saliva. Although antioxidants may potentially mitigate radiotherapy-induced complications, their clinical application requires caution due to the possibility of protecting the tumor cells, thereby potentially compromising the oncologic treatment outcomes.