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

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. 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. 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. 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.

Adherence to conflicts of interest policy in Cochrane reviews where authors are also editorial board members: A cross-sectional analysis

Cochrane devolves most editorial governance of the Cochrane Database of Systematic Reviews (CDSR), including title prioritization, protocol registration, peer-review, editorial oversight and subsequent review deposition, to specific Cochrane Review Group (CRG) editorial boards. Current Cochrane policy stipulates authors of reviews who are also members of the supporting CRG declare this non-financial conflict of interest and confirm no involvement in the review editorial process. The aim of this cross-sectional analysis was to assess adherence to Cochrane's editorial conflict of interest policy. All 260 published Cochrane reviews (CR) in issues 1 to 6 from 2019 of the CDSR were reviewed. A total of 133 (51.2%, 133/260) of CRs had at least one author that was also listed as an editor in the CRG. Of these, only five (3.8%, 5/133) appropriately declared the conflict according to Cochrane policy. In 6.5% (17/133) CRs, the contact author had a leading editorial position within the CRG and in only four of 17 was this declared according to Cochrane policy. No CR with the contact author who also had a leading editorial position described methods to prevent any potential issues related to this scenario during the editorial process in accordance with Cochrane policy. We propose a specific form to improve the transparency and reliability of editorial conflict of interest reporting in CRs. The suggested form can be adapted to other contexts.

Impact of general anaesthesia in overall and disease-free survival compared to other types of anaesthesia in patients undergoing surgery for cutaneous melanoma: a systematic review and meta-analysis protocol

INTRODUCTION

Cutaneous melanoma is an aggressive type of skin cancer. Anaesthetic agents may have an impact on the immune response, postoperative neurohumoral response and tumour progression. This systematic review aims to evaluate the impact of general anaesthesia on overall and disease-free survival compared with other types anaesthesia in patients undergoing surgery for cutaneous melanoma.

METHODS AND ANALYSIS

The review will analyse data from controlled and observational studies of patients undergoing surgery for melanoma under general anaesthesia compared with other types of anaesthesia. The primary outcomes are overall survival and disease-free survival. The secondary outcomes are health-related quality of life, time to tumour progression, distant disease-free survival, time to treatment failure, cancer-specific survival, biochemical recurrence, return of intended oncological therapy, days alive and out of the hospital at 90 days, cost analysis and adverse events. A comprehensive literature search will be performed using the MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, LILACS and IBECS databases. Grey literature will also be searched. Risk of methodological bias will be assessed using The Cochrane Collaboration's revised tool for assessing risk of bias in randomised trials (RoB 2.0) and the Newcastle-Ottawa scale. Two reviewers will independently assess the eligibility of studies and risk of bias; a third author will solve discrepancies. One author will perform data extraction and the other will check the process and data. Qualitative analysis will be carried out using all included studies. A meta-analysis using a random-effects model for pooled risk estimates will be carried out for the two main outcomes and for selected secondary outcomes if they conform to previously stated criteria. The GRADE approach will be used to summarise the quality of evidence.

ETHICS AND DISSEMINATION

Ethics approval is not required as we analyse data from previously reported studies.

PROSPERO REGISTRATION NUMBER

CRD42018114918.