1 Bryant A, et al. BMJ Open 2022;12:e060183. doi:10.1136/bmjopen-2021-060183 Open access Residual disease after primary surgery for advanced epithelial ovarian cancer: expert elicitation exercise to explore opinions about potential impact of publication bias in a planned systematic review and meta-analysis Andrew Bryant , 1 Michael Grayling, 1 Shaun Hiu, 1 Ketankumar Gajjar, 2 Eugenie Johnson, 1 Ahmed Elattar, 3 Luke Vale, 1 Dawn Craig, 1 Raj Naik 4 To cite: Bryant A, Grayling M, Hiu S, et al. Residual disease after primary surgery for advanced epithelial ovarian cancer: expert elicitation exercise to explore opinions about potential impact of publication bias in a planned systematic review and meta-analysis. BMJ Open 2022;12:e060183. doi:10.1136/ bmjopen-2021-060183 ► Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (http://dx.doi.org/10.1136/ bmjopen-2021-060183). Received 14 December 2021 Accepted 03 August 2022 For numbered affiliations see end of article. Correspondence to Dr Andrew Bryant; andy.bryant@ncl.ac.uk Original research © Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. ABSTRACT Objectives We consider expert opinion and its incorporation into a planned meta-analysis as a way of adjusting for anticipated publication bias. We conduct an elicitation exercise among eligible British Gynaecological Cancer Society (BGCS) members with expertise in gynaecology. Design Expert elicitation exercise. Setting BGCS. Participants Members of the BGCS with expertise in gynaecology. Methods Experts were presented with details of a planned prospective systematic review and meta-analysis, assessing overall survival for the extent of excision of residual disease (RD) after primary surgery for advanced epithelial ovarian cancer. Participants were asked views on the likelihood of different studies (varied in the size of the study population and the RD thresholds being compared) not being published. Descriptive statistics were produced and opinions on total number of missing studies by sample size and magnitude of effect size estimated. Results Eighteen expert respondents were included. Responders perceived publication bias to be a possibility for comparisons of RD <1 cm versus RD=0 cm, but more so for comparisons involving higher volume suboptimal RD thresholds. However, experts’ perceived publication bias in comparisons of RD=0 cm versus suboptimal RD thresholds did not translate into many elicited missing studies in Part B of the elicitation exercise. The median number of missing studies estimated by responders for the main comparison of RD<1 cm versus RD=0 cm was 10 (IQR: 5–20), with the number of missing studies influenced by whether the effect size was equivocal. The median number of missing studies estimated for suboptimal RD versus RD=0 cm was lower. Conclusions The results may raise awareness that a degree of scepticism is needed when reviewing studies comparing RD <1 cm versus RD=0 cm. There is also a belief among respondents that comparisons involving RD=0 cm and suboptimal thresholds (>1 cm) are likely to be impacted by publication bias, but this is unlikely to attenuate effect estimates in meta-analyses. INTRODUCTION Residual disease (RD) after upfront primary debulking surgery (PDS) for advanced epithelial ovarian cancer (EOC) is believed to be a key determinant of overall survival (OS). A recent prognostic factor systematic review protocol aims to demonstrate the superiority in terms of OS of the complete removal of RD in advanced EOC compared with leaving macroscopic disease (that is, the surgeon leaving some visible disease). 1 However, much of the evidence in this area comes from small and/or retrospec- tive studies. Relying on such studies to draw conclusions may be unsound. One reason for this relates to possible publication biases, which may be more pronounced for small, STRENGTHS AND LIMITATIONS OF THIS STUDY ⇒ In our elicitation exercise, designed in collaboration with senior gynae-oncologists, the number of re- spondents (n=18) was sufficient to provide a solid basis for meaningful conclusions to be drawn in an area of uncertainty. ⇒ Part A of the elicitation identifies areas where publi- cation bias is of concern, but the questions asked do not provide an indication of the direction of any bias. ⇒ Therefore, in Part B of our elicitation exercise, we collected information that would enable any planned meta-analysis estimates to be adjusted for the an- ticipated impact of publication bias. ⇒ The approach adopted is inexpensive and easy to design and administer and did not rely on any con- tact with participants, who were able to complete at their own convenience. ⇒ However, answers given by the experts to open- ended questions were prone to an ‘extreme answer bias’. on April 27, 2024 by guest. 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