1066: endoscopic screening and risk of colorectal cancer according to type 2 diabetes status

Current recommendations for CRC screening have not accounted for type 2 diabetes (T2D) status. It remains unknown whether the CRC-preventive benefit of endoscopic screening and the recommended age for screening initiation differ by T2D. Among 166,307 women (Nurses' Health Study I and II, 1988-2017) and 42,875 men (Health Professionals Follow-up Study, 1988-2016), endoscopic screening and T2D diagnosis were biennially updated. We calculated endoscopic screening-associated hazard ratios (HRs) and absolute risk reductions (ARRs) for CRC incidence and mortality according to T2D, and age-specific CRC incidence according to T2D. During a median of 26 years of follow-up, we documented 3,457 CRC cases and 1,129 CRC deaths. Endoscopic screening was associated with a similar HR of CRC incidence in the T2D and non-T2D groups (P-multiplicative interaction=0.57). In contrast, the endoscopic screening-associated ARR for CRC incidence was higher in the T2D group (2.36%, 95%CI, 1.55-3.13%) than in the non-T2D group (1.73%, 95%CI, 1.29-2.16%) (P-additive interaction=0.01). Individuals without T2D attained a 10-year cumulative risk of 0.35% at the benchmark age of 45 years, whereas those with T2D reached this threshold risk level at the age of 36 years. Similar results were observed for CRC mortality. In conclusion, the absolute benefit of endoscopic screening for CRC prevention may be substantially higher for individuals with T2D compared to those without T2D. Although T2D is comparatively rare prior to the 5th decade of life, the rising incidence of young-onset T2D and heightened CRC risk associated with T2D support the consideration of earlier endoscopic screening in individuals with T2D.