Introduction Colorectal cancer (CRC) is a leading cause of morbidity and mortality in England. Both 1- and 5-year survival rates are greatly improved when the disease is diagnosed early; however, most cases are diagnosed late, and the prognosis for survival is generally poor. The aim of this study was to identify factors associated with receiving a late-stage diagnosis.

Methods We performed a clinical audit of 1,015 patients diagnosed with CRC at St Mark’s Hospital between January 2017 and December 2020. Variations in Lymph node involvement and distant organs (at the time of diagnosis) were assessed using multivariate logistic regression. All analyses were performed using SPSS (Ver 27.0).

Results The sample was comprised of 584 (57.5%) men and 431 (42.5%) women, from a range of ethnic backgrounds: White British/Irish (413, 40.7%), Other White background (67, 6.6%), South Asian (176, 17.3%), Other Asian background (84, 8.3%), Any Black background (95, 9.4%) and Any Other/Mixed background (42, 4.1%). The mean age and Index of Multiple Deprivation score of patients were 70.29 years and 20.38, respectively. The most common route to diagnosis was GP referral (554, 54.6%), followed by A&E (218, 21.5%), Other (150, 14.8%) and Screening (93, 9.2%). Data were missing for 279 (27.5%) and 318 (31.3%) individuals included in the predictors of lymph node involvement and predictors of distant metastasis analyses (respectively), meaning that 736 (72.5%) and 697 (68.7%) individuals were included.

The odds of lymph involvement decreased with age (aOR: 0.98; 95%CIs: 0.97, 1.00; p=0.01), were higher among South Asian adults compared with White British adults (aOR: 1.89; 95%CIs: 1.09, 3.28; p=0.023), and were lower among patients diagnosed through Screening or Other pathways compared with A&E (aOR: 0.41, 95%CIs: 0.24, 0.69; p=0.002 and aOR:0.40, 95%CIs: 0.23, 0.71; p=0.015, respectively). The odds of metastasis were higher among adults from Any Black Background compared with White British adults (aOR: 2.07, 95%CI: 1.14, 3.88; p=0.018), and were lower among those diagnosed through a GP referral or screening, when compared with those diagnosed through A&E (aOR: 0.50, 95%CIs: 0.32, 0.79; p=0.003 and aOR: 0.14, 95%CIs: 0.05, 0.38; p=0.001).

Conclusions Screening is associated with reduced odds of being diagnosed with CRC at a stage when lymph nodes and distant organs are affected, yet fewer cases are diagnosed via this pathway than any other. To determine whether there are missed opportunities to detect disease through screening, and whether inequalities in screening participation may account for the advanced stage at diagnosis observed for some ethnic minority groups, we will extract data on screening history.