The impact of diabetes on cancer detection during the prevalence round of a national screening program for colorectal cancer

Abstract

Aims Diabetes is associated with a higher risk of colorectal cancer (CRC) and inferior survival after CRC. Screening may enable the early detection of CRC. We aimed to assess the impact of diabetes on cancer detection and disease stage during the prevalence round of a national CRC screening program. Methods We performed a register‐based cohort study based on the randomized procedure for inviting Danish residents aged 50–74 years to the prevalence round of national CRC screening program in 2014–2017. By comparing the random half of the population who had been invited by 1 May 2016 with the not yet invited half, the effect of screening was assessed by the detection of CRC and disease stage among individuals with and without diabetes. Further, the impact of diabetes on the screening participation rate was calculated. Results By randomisation, 504,673 individuals had been invited to the CRC screening by 1 May 2016, and 549,359 individuals had not yet been invited. The diabetes prevalence was 10% in both groups. When comparing those not yet invited to those invited, the effect of screening on the number of detected cancers per 100,000 individuals was higher in those with diabetes (from 207 to 494 cancers) than in those without diabetes (from 147 to 364 cancers), and screening resulted in overall higher proportions of stage I cancer. Among those invited to screening, the participation rate was 9.1% lower (95% CI: 8.7%–9.5%) in individuals with versus without diabetes. Conclusions Despite a lower participation rate, the effect of CRC screening was higher in individuals with diabetes.

Screen test

“…In this issue of Diabetic Medicine, registry data from Denmark show that, among those invited for screening, participation was lower in people with diabetes but that the effect of screening was higher in people with diabetes. 4 This additional effectiveness is important for a group at higher risk and, taken with the participation data, suggests that colorectal screening for people with diabetes may be prioritised and that education and support to optimise participation may be required. The differential effectiveness of screening for cancers in people with diabetes, compared with people without diabetes, has not been looked at for other cancers but is an important area and may lead to differences in guidelines for people with diabetes to optimise the impact of screening on future disease.…”

“…For this reason, the availability and attendance at colorectal screening are of high importance for people with diabetes. In this issue of Diabetic Medicine, registry data from Denmark show that, among those invited for screening, participation was lower in people with diabetes but that the effect of screening was higher in people with diabetes 4 . This additional effectiveness is important for a group at higher risk and, taken with the participation data, suggests that colorectal screening for people with diabetes may be prioritised and that education and support to optimise participation may be required.…”