SP1.1.5Association between prior screening involvement and presentation and outcomes in patients with colorectal cancer

Aims Population bowel cancer screening (BCS) is well established, however many patients still present acutely or with advanced disease. Within a cohort of patients with colorectal cancer (CRC), this study aimed to analyse the relationship between prior engagement with the screening programme and mode of presentation, disease stage and survival. Methods All patients diagnosed with CRC from 2011-2014 in West of Scotland were identified from a regional database and linked into the Bowel Screening dataset for screening participation within two years preceding diagnosis. Results 6551 patients were diagnosed with CRC, 19% (n = 1217) through screening. 39% of patients were not invited for screening and 29% of patients did not respond to invite. Non-response to invite was associated with male sex, increasing age, socioeconomic deprivation, co-morbidity and smoking (all p < 0.001). 13% had previously returned negative screening tests. Negative screening was associated with female sex, anaemia, right sided, poorly differentiated and EMVI positive tumours, and screening with gFOBT versus FIT (all p ≤ 0.001).  2% did not undergo further investigation of a positive test, and <1% had a negative colonoscopy. Participation in screening was associated with reduced emergency presentations (8%vs22%), lower TNM Stage, and improved 3-year CSS (88%vs74%) and OS (85%vs69%) (all p < 0.001). Conclusion Most new cases of CRC are diagnosed outwith the screening programme, predominantly due to non-invite/failure to respond to invite. This has a significant association with adverse outcomes including emergency presentation, advanced TNM stage and poorer survival. Further work is required to increase screening uptake and widen access to BCS.