Development of a core outcome set for clinical trials in squamous cell carcinoma: study protocol for a systematic review of the literature and identification of a core outcome set using a Delphi survey

Background: Squamous cell carcinoma (SCC) is a common skin cancer that poses a risk of metastasis. Clinical investigations into SCC treatment are common, but the outcomes reported are highly variable, omitted, or clinically irrelevant. The outcome heterogeneity and reporting bias of these studies leave clinicians unable to accurately compare studies. Core outcome sets (COSs) are an agreed minimum set of outcomes recommended to be measured and reported in all clinical trials of a given condition or disease. Although COSs are under development for several dermatologic conditions, work has yet to be done to identify core outcomes specific for SCC. Methods/design: Outcome extraction for COS generation will occur via four methods: (1) systematic literature review; (2) patient interviews; (3) other published sources; and (4) input from stakeholders in medicine, pharmacy, and other relevant industries. The list of outcomes will be revaluated by the Measuring PRiority Outcome Variables via Excellence in Dermatologic surgery (IMPROVED) Steering Committee. Delphi processes will be performed separately by expert clinicians and patients to condense the list of outcomes generated. A consensus meeting with relevant stakeholders will be conducted after the Delphi exercise to further select outcomes, taking into account participant scores. At the end of the meeting, members will vote and decide on a final recommended set of core outcomes. The Core Outcome Measures in Effectiveness Trials (COMET) organization and the Cochrane Skin Group - Core Outcome Set Initiative (CSG-COUSIN) will serve as advisers throughout the COS generation process. Discussion: Comparison of clinical trials via systematic reviews and meta-analyses is facilitated when investigators study outcomes that are relevant and similar. The aim of this project is to develop a COS to guide use for future clinical trials.