Effects of Propofol-Based Anesthesia on Tumor Recurrence Biomarkers in Breast Cancer: A Protocol for Systematic Review and Meta-Analysis of RCTs

Backgroung: breast cancer is a leading cause of morbidity and mortality among women worldwide. Emerging evidence suggests that anesthetic techniques used during cancer surgery may modulate perioperative immune and inflammatory responses, influencing tumor biology and long-term outcomes. Propofol-based total intravenous anesthesia has been associated with immunomodulatory properties that may affect pathways involved in tumor recurrence. Objective: this protocol describes a systematic review and meta-analysis of randomized controlled trials (RCTs) designed to evaluate the effects of propofol-based anesthesia, compared with volatile anesthetics, on biomarkers related to tumor recurrence in adult patients undergoing breast cancer surgery. Methods: the review will be conducted in accordance with PRISMA guidelines. A comprehensive search will be performed in Scopus, Web of Science, MEDLINE/PubMed, Embase, CINAHL, and Cochrane databases, without restrictions on language or publication date. Eligible RCTs will report perioperative changes in biomarkers reflecting: (a) systemic inflammatory response (interleukin-6, tumor necrosis factor-alpha, interleukin-10); (b) antitumor cellular immunity (natural killer cell activity, CD4+ and CD8+ lymphocyte counts); (c) tumor biology and recurrence potential (circulating tumor cells and HER/HER2 expression). Study selection, data extraction, and risk-of-bias assessment will be conducted independently using Rayyan, RoB 2, and GRADE. Quantitative synthesis will be performed if appropriate, using random-effects meta-analysis. Expected significance: the findings of this review may inform clinical decision-making regarding anesthetic choice in oncologic surgery and contribute to evidence-based perioperative strategies to minimize the risk of tumor recurrence in breast cancer patients.