Quantifying and mitigating the impact of the COVID-19 pandemic on outcomes in colorectal cancer

Background: The COVID-19 pandemic has caused disruption across cancer pathways for diagnosis and treatment. In England, 32% of colorectal cancer (CRC) is diagnosed via urgent symptomatic referral from primary care, the "2-week-wait" (2WW) pathway. Access to routine endoscopy is likely to be a critical bottleneck causing delays in CRC management due to chronic limitation in capacity, acute competition for physician time, and safety concerns. Methods: We used age-specific, stage-specific 10 year CRC survival for England 2007-2017 and 2WW CRC cases volumes. We used per-day hazard ratios of CRC survival generated from observational studies of CRC diagnosis-to-treatment interval to model the effect of different durations of per-patient delay. We utilised data from a large London observational study of faecal immunochemical testing (FIT) in symptomatic patients to model FIT-triage to mitigate delay to colonoscopy. Findings: Modest delays result in significant reduction in survival from CRC with a 4-month delay resulting across age groups in ≥20% reduction in survival in Stage 3 disease and in total over a year, 1,419 attributable deaths across the 11,266 CRC patients diagnosed via the 2WW pathway. FIT triage of >10 ug Hb/g would salvage 1,292/1,419 of the attributable deaths and reduce colonoscopy requirements by >80%. Diagnostic colonoscopy offers net survival in all age groups, providing nosocomial COVID-19 infection rates are kept low (<2.5%). Interpretation To avoid significant numbers of avoidable deaths from CRC, normal diagnostic and surgical throughput must be maintained. An accrued backlog of cases will present to primary care following release of lockdown, supranormal endoscopy capacity will be required to manage this without undue delays. FIT-triage of symptomatic cases provides a rational approach by which to avoid patient delay and mitigate pressure on capacity in endoscopy. This would also reduce exposure to nosocomial COVID-19 infection, relevant in particular to older patient groups. Funding: Breast Cancer Now, Cancer Research UK, Bobby Moore Fund for Cancer Research, National Institute for Health Research (NIHR).