The Missing Cohort: A comparative audit of colorectal 2-week wait referrals during the pandemic versus historic referrals to quantify the risk profile of patients who have not been referred during the COVID19 pandemic

Background: The COVID19 pandemic has resulted in a significant reduction in referrals to the colorectal cancer 2-week wait pathway. The aim of this study was to describe this 'missing cohort of referrals' by comparing the characteristics of referrals made during the pandemic with historic referrals. Methods: Demographics, index of multiple deprivation deciles (IMD), labs, faecal immunochemical tests (FIT) and cancer outcomes data of referrals between January 2015 and September 2020 were included. The historic cohort (Jan 2015 to Feb 2020) was compared with the pandemic cohort (Apr to Sep 2020). Referrals made in March 2020 were excluded. Results: 16704 referrals were included -14800 historic, 1583 pandemic and 321 excluded. There was no difference in age (median 69 years), gender (47% male), ethnicity (95% Caucasian), IMD (median 7) or cancer incidence (any malignancy 4.7% vs 5.0%, colorectal cancer 3.1% vs 3.9%). There were fewer referrals with iron-deficiency anaemia (11% vs 15%, P < 0.01) due to introduction of a separate pathway in 2019. FIT testing doubled during the pandemic (64% vs 31% in 2019, P < 0.001) after it was made mandatory. Conclusion: Clinical risk and outcome characteristics of pandemic referrals did not differ significantly from historic referrals. They were neither a selective high-risk cohort due to improved triage nor a low-risk cohort because of concerns of high-risk patients attending hospital during the pandemic. The 'missing cohort' are likely to have similar clinical characteristics as historic referrals including 5% cancer incidence and 10% polyp incidence. Urgent action is required to avoid further harm to these patients.