Effect of Regional Anesthesia on Oncological Outcomes (Meta-Analysis)

Metastatic processes remain the main cause of deaths in oncology. Methods of anesthesia, in particular regional anesthesia, are considered as potential modulators of the immune response and metastatic spread. The ambiguity of the available data on the effect of regional and general anesthesia on metastatic spread is partly due to the fact that general anesthetic in combined anesthesia is quite often not taken into account, and this, in turn, masks the possible influence of regional anesthesia. The purpose of this meta-analysis was to make a comparative assessment of the effect of general anesthesia and general anesthesia in combination with regional anesthesia on the relapse-free and overall survival of cancer patients after surgery. Materials and methods. We analyzed 8 randomized controlled trials involving 1822 patients and comparing the groups of cancer patients who were operated either under general anesthesia (total intravenous (TIVA) or inhalation (IA)), or general anesthesia in combination with regional anesthesia (TIVA+RA or IA+RA, respectively). Trial using combinations of inhaled and intravenous anesthetics was excluded from the analysis for a more accurate assessment of the effect of regional anesthesia. The study complies with the recommendations of the Cochrane Community and PRISMA standards. The protocol was registered on the INPLASY platform. We used PubMed, Google Scholar and CENTRAL databases. We used a subgroup analysis and GRADE tool to assess the quality of evidence. Results. There were no statistically significant differences in relapse-free and overall survival when comparing different anesthesia methods. For a relapse-free survival, comparing TIVA vs TIVA+RA resulted in no significant difference : OR=1.20 [95% CI 0.92-1.55]; when IA vs IA+RA were compared, OR=1.10 [95% CI 0.94-1.29]. Similar results were obtained for overall survival. Conclusion. Based on the meta-analysis results, regional anesthesia had no effect on relapse-free and overall survival in oncosurgery patients.