Abstract 4850: Sex differences in cancer incidence: Prospective analyses in the UK Biobank

Abstract Background: Exploring the underlying sex differences in cancer incidence and the potential reasons for the differences may provide insights into cancer aetiology. We aimed to examine the differences in incidence of cancer between men and women in the UK Biobank and to assess the extent to which any disparities persisted after accounting of established risk factors for those cancers. Methods: Prospective analyses were performed in the UK Biobank to examine associations between sex and risk of 15 cancers (and 13 subtypes) common to both sexes using minimal and multivariable-adjusted Cox proportional hazards regression models. Results: Over an average of 10.5 (SD 2.2) years of follow-up, 46,081 incident cancers were identified in 470,771 individuals (aged 37 to 73 years at recruitment); 24,634 cancers (53.5%) diagnosed in women and 21,447 (46.5%) in men. While some differences in cancer risk between the sexes were attenuated in the comprehensively multivariable-adjusted models, men compared to women remained at greater risk of cancers at eight sites. Compared to women, men had higher risks of oesophageal adenocarcinoma (hazard ratio 5.45; 95% confidence interval, 4.17-7.12), gastric cardia (3.65; 2.48-5.38), bladder (3.47; 2.85-4.24), oral (2.06; 1.69-2.51), liver (1.91; 1.48-2.47), kidney (1.77; 1.51-2.09), rectum (1.7; 1.47-1.96), and leukaemia (1.43; 1.21-1.69); while women had higher risks of cancers of the breast, thyroid (0.36; 0.26-0.49), anus (0.41; 0.26-0.64), gallbladder (0.56; 0.31-0.99), and lung adenocarcinoma (0.72; 0.62-0.84). Conclusion: Further studies of unexplained sex differences may provide insights into cancer aetiology. Citation Format: Maira Khan, Keren Papier, Kirstin Pirie, Joshua Atkins, Tim Key, Ruth Travis. Sex differences in cancer incidence: Prospective analyses in the UK Biobank [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4850.