Differences between men and women with respect to colorectal cancer mortality despite screening colonoscopy

Women aged 55 to 59 years have a similar prevalence rate and number needed to screen for colorectal adenomas as men at a ten years younger age. The aim of this study was to determine sex specific differences in colorectal cancer mortality and estimate the association with adenomas at screening colonoscopy.This retrospective study analyzed 323,139 individuals who underwent colonoscopy within a national colorectal cancer screening program in Austria between 01/2007 and 12/2020.Median age was (60 years [IQR 54-67]) and sex distribution in all age groups was nearly identical. Men had significantly higher odds to have an adenoma or serrated polyp, low risk polyps, high-risk polyps, or colorectal cancer detected at colonoscopy than women (OR 1.83 [1.80-1.86], OR 1.46 [1.44-1.49], OR 1.74 [1.69-1.80], and OR 1.87 [1.70-2.05] respectively). Strikingly, male sex, when compared to female sex, was associated with an almost 2-fold (HR 1.67 [1.05-2.67]) increased risk to die from colorectal cancer when an adenoma or serrated polyp, and a 4-fold (HR 4.14 [2.72-6.3]) increased risk when a high-risk polyp was found at the screening colonoscopy. The cumulative incidence for death of colorectal cancer for 60-year-old individuals was 8.5-fold higher in men as compared to women. Markedly, this gender gap narrowed with increasing age while the difference in deaths of other causes remained similar in all age groups.Our findings strengthen the necessity of sex specific screening recommendations. Importantly, further prospective studies should focus on sex difference in tumor biology to propose personalized surveillance guidelines.