Lack of precision in the reporting of sex and gender in cancer clinical trials with a PRO endpoint: a systematic review

Background Sex and gender are acknowledged as pivotal variables in clinical research. However, the differences between the concepts are frequently neglected in medical research, resulting in limited generalizability of research findings and potential bias. This review portrays current reporting of sex and/or gender in cancer clinical trials with a patient-reported outcome (PRO) endpoint. Methods Pubmed was searched to identify randomized controlled trials in patients with bladder, colorectal, and lung cancer, published between 2019 and February 2022. A double-review procedure was applied using the software DistillerSR. The data extraction form included information on the terms used to describe sex and/or gender. The Sex and Gender Equity in Research (SAGER) guidelines checklist was used for quality appraisal. Results The Pubmed search resulted in 2,450 identified records, of which 184 met the eligibility criteria. The term sex was used in 54.9%, gender in 21.2%, and both terms in 17.4% of the references, while 6.5% reported none. 39.1% of trials used the terms sex and/or gender correctly (i.e., referring to biological or social categories) and consistently. 60.9% of trials combined the terms in varying ways, which was not due to reporting of both concepts but rather to the interchangeable use of sex and gender. Regarding compliance with the SAGER guidelines checklist, the median number of items meeting the requirements was 2 out of 17. Conclusions Our review shows that most trials lack precision in reporting sex and/or gender, highlighting the educational need for distinguishing these concepts in the field of clinical trials with PRO endpoints. The synonymous use of the terms sex and gender does not do justice to their different conceptualizations and can hinder further research that is inclusive of sex and/or gender. Raising awareness and compliance with the SAGER guidelines in cancer clinical trials is needed to enhance the credibility of findings drawn regarding sex and/or gender differences.