Biological sex disparity in survival outcomes following treatment for renal cell carcinoma: A systematic review and meta-analysis

Introduction: Renal cell carcinoma (RCC), a type of kidney cancer has biological sex-based differences that play a role in cancer incidence. Specifically, the incidence of urinary system cancers in men is two times greater than in women, while the incidence of genital cancers is three times greater. There is conflicting epidemiologic and limited evidence in the literature to suggest apparent biological sex discrepancy. The primary objective of this review and meta-analysis is to synthesize evidence to understand biological sex disparity in the survival outcomes of RCC following any treatment intervention. Methods: A three-step search strategy was utilized in this review. We searched MEDLINE, EMBASE and PsycINFO databases for manuscript on biological sex differences in treatment outcomes. Study screening, critical appraisal, and data extraction were executed independently by pairs of reviewers among co-authors. Studies that had any form of treatment modality in the management of RCC were included. Study designs included observational studies in the form of prospective and retrospective studies that utilized cox proportional hazard assumption to conduct survival analysis. The data synthesis was carried out using the R metafor software package (Software version of 1.2.8) and Microsoft Office Excel 2019 package (Microsoft Corporation, USA). The random effects model was estimated using restricted maximum likelihood estimation (REML). Data synthesis included narrative review and meta-analysis. Results: We had 23 eligible studies for this review. On review of the full text, 35 studies were excluded due to irrelevances to measure estimates utilized. Finally, 12 studies were selected for the meta-analysis with a total of n = 21,2453 individuals. Females had a better survival outcome following a treatment intervention for RCC than their male counterpart [Mean effect size = −0.1737 (95 % CI: −0.2524, −0.0949)]. Conclusion: Females were more likely to be cancer free than their male counterpart following treatment for RCC. This finding will inform appropriate decision making for stakeholders.