Relationship Between Plasma Vitamin E Levels and Risk Groups in Prostate Cancer Patients Undergoing Radical Radiotherapy

Objective: To evaluate the association between plasma vitamin E levels and clinical risk groups in patients with prostate cancer undergoing radical radiotherapy, assessing the frequency of deficiency and its potential relationship with clinical and epidemiological factors. Background: Prostate cancer is one of the most prevalent malignancies worldwide, and radiotherapy, although effective, induces oxidative stress, affecting both tumor and normal tissues. Vitamin E, a key antioxidant, may attenuate treatment-related oxidative damage. Limited evidence suggests a potential association between low vitamin E levels, elevated prostate-specific antigen (PSA), and more aggressive tumor behavior. Methods: This was a retrospective, longitudinal study of 65 patients treated with radical radiotherapy between 2019 and 2022 at Clínica de Radioterapia do Ingá, Niterói, Brazil. Serum vitamin E levels were quantified using HPLC before and after treatment, alongside baseline PSA assessment. Vitamin E deficiency was defined as values < 1.0 mg/dL. Results and Discussion: A significant reduction in vitamin E levels was observed after treatment (p < 0.0001), with 54.3% of patients meeting criteria for deficiency. Lower plasma vitamin E levels were associated with elevated PSA (p < 0.005) and higher tumor aggressiveness. Body mass index (BMI) > 28 and absence of smoking were associated with better preservation of vitamin E levels. Reduced vitamin E levels were correlated with increased genitourinary and gastrointestinal toxicity. Implications: Monitoring vitamin E levels during radiotherapy may help mitigate treatment-related toxicity and improve patient quality of life. Supplementation could represent a promising adjunctive strategy. Originality/Value: This study addresses a significant gap in the literature by proposing vitamin E as a potential prognostic biomarker to support personalized therapeutic strategies in prostate cancer.