Sex and gender differences in cancer research and its application to clinical oncology and therapeutics.

Objectives: Oncology has exhibited gender inequalities in leadership and authorship, alongside significant differences in cancer incidence, mortality, and survival rates between sexes. These disparities highlight the urgent need for sex- and gender-specific scientific reporting to improve research accuracy and clinical applications and encourage the same opportunities in research careers.

Methods: The integration of gender perspective in cancer was assessed by analyzing scientific publications comparing 2011 and 2021. The correlation between the gender of the authors and the different types of cancer studied was examined, as well as the inclusion of the sex and gender variables in the content of the research. The study was STROBE compliant.

Results: 3,194 papers were published in 2011 and 6,781 in 2021, signed by at least one Spanish institution. The ratio of female authors per article was 0.39 in 2011 compared to 0.43 in 2021, reaching parity. Gender bias in the content of scientific articles, as measured by a 10-item checklist, showed an unfavorable score for perspective integration in both years (1.7/10 and 1.8/10, respectively). In terms of the Gender Balance Index in the analyzed samples of the papers (cells, animals or volunteers/patients), there was an increase from 29 % in 2011 to 43 % in 2021. Breast cancer research was dominated by female authors, whereas lung cancer research was predominantly by parity or male authorship, and no differences in author groups in colorectal cancer research were observed.

Conclusions: Greater efforts and commitments are needed from government institutions, funding agencies, and academic structures to promote sex/gender integration in cancer research.