General anaesthesia versus other types of anaesthesia in patients undergoing surgery for treatment of cutaneous melanoma: a systematic review and meta-analysis

Background General and local anaesthetics alter tumour behaviour in experimental models. Objectives To investigate the relationship between general anaesthesia and recurrence or survival in patients who received surgery for malignant melanoma. Materials & Methods A meta-analysis was performed based on a comprehensive literature search. Controlled and observational studies of patients undergoing surgery for melanoma under general anaesthesia, compared with other types of anaesthesia, were included. The primary outcomes were overall survival and disease-free survival. The secondary outcomes included cancer-specific survival, cost analysis, and adverse events. Risk of bias was assessed. Individual study information was summarized. The meta-analysis was performed using a random-effects model. The GRADE approach was used to summarise the certainty of evidence. Results Eight studies were included (n = 5,832). The use of general anaesthesia was not associated with any statistical difference in overall survival (p = 0.087; 1 NRS; n= 104; very low certainty of evidence) or disease-free survival (HR: 1.266; 95% CI: 0.904-1.773; p = 0.169; 1 NRS; n = 281; very low certainty of evidence). However, general anaesthesia was associated with worse melanoma-specific survival (HR: 1.46; 95% CI: 1.22-1.68: p < 0.00001; 3 NRS; n = 4654; low certainty of evidence). Three studies reported increased intraoperative costs associated with the use of general anaesthesia (3 NRT; n = 513; very low certainty of evidence). No study adequately reported other primary or secondary outcomes. Conclusion General anaesthesia may reduce melanoma-specific survival in patients undergoing surgery for treatment of cutaneous melanoma. We are uncertain whether general anaesthesia impacts the other reported outcomes.