Sex in Bladder cancer research: an overview

Sex is increasingly being reported as clinically important variable in the outcome of bladder cancer treatment. But the application of the Sex as a Biological Variable research design, analysis and reporting practices remains limited in biomedical research, dominated by the common use of sex-neutral language with regard to research participants. This study aimed to establish the prevalence of the Sex as a Biological Variable principles in bladder cancer research. Preclinical and clinical studies published in three urology journals were reviewed for the reporting of cells, animal or patient sex and the inclusion of sex as a biological variable in both study design and data analysis. A total of 489 articles were screened from which 133 met the inclusion criteria: 2 (2%) preclinical and 131 (98%) clinical studies. Three articles reported separate outcome data for male and female. Where sex of participants was stated 111/133 (83%); 3 manuscripts (97%) reported a larger number of male participants, compared to females. Only 47 (35%) used sex as a variable in data analysis from which 10 (21%) showed statistically significant difference between their male and female bladder cancer patient cohorts. The inclusion of sex as a biological variable is poorly practiced in bladder cancer research and should be more consistently requested.