Dexmedetomidine as an Adjuvant to Nerve Block for Cancer Surgery: A Systematic Review and Meta-Analysis

Background/Objectives: Our understanding of dexmedetomidine, as an adjuvant to nerve blocks in cancer surgery, is characterized by a current lack of compelling evidence, and it remains unknown whether the potential benefits of use outweigh the risks. The aim of the study was to evaluate the benefit and safety profiles of dexmedetomidine as an adjuvant to nerve blocks in cancer surgery. Methods: Systematic searches were conducted in MEDLINE, ScienceDirect, Cochrane Library, Springer, medRxiv, and Scopus up to 17 May 2024. Risk ratios (RR) for binary outcomes and standardized mean differences (SMDs) for continuous outcomes were quantified. Results: Twenty studies were identified. In breast cancer surgery, the use of dexmedetomidine reduced 24 h total morphine consumption (SMD = -1.99 [95% CI -3.01 to -0.98], p = 0.0001, I2 = 91%, random effects) and prolonged the requirement for morphine rescue analgesia (SMD = 2.98 [95% CI 0.01 to 5.95], p = 0.05, I2 = 98%, random effects). In abdominal cancer surgery, the dexmedetomidine group had lower total sufentanil consumption (SMD = -1.34 [95% CI -2.29 to -0.40], p = 0.005, I2 = 84%, random effects). Dexmedetomidine reduced the VAS score and decreased postoperative nausea and vomiting (PONV). No studies using dexmedetomidine reported serious adverse events. Conclusions: Using dexmedetomidine as an adjuvant to nerve blocks in cancer surgery could lower the VAS pain score and prolong the regional anesthesia duration, which would lead to a decrease in total opioid consumption and possibly contribute to fewer PONV events. Furthermore, the reports of no serious adverse events indicate its good safety profile.