Short-term outcomes of a COVID-adapted triage pathway for colorectal cancer detection

Abstract

Aim: The dramatic curtailment of endoscopy and CT colonography capacity during the coronavirus pandemic has adversely impacted timely diagnosis of colorectal cancer (CRC). We describe a rapidly implemented COVID-adapted diagnostic pathway to mitigate risk and maximize cancer diagnosis in patients referred with symptoms of suspected CRC.

Method: The 'COVID-adapted pathway' integrated multiple quantitative faecal immunochemical tests (qFIT) to enrich for significant colorectal disease with judicious use of CT with oral contrast to detect gross pathology. Patients reporting 'high-risk' symptoms were triaged to qFIT+CT and the remainder underwent an initial qFIT to inform subsequent investigation. Demographic and clinical data were prospectively collected. Outcomes comprised cancer detection frequency.

Results: Overall, 422 patients (median age 64 years, 220 women) were triaged using this pathway. Most (84.6%) were referred as 'urgent suspicious of cancer'. Of the 422 patients, 202 (47.9%) were triaged to CT and qFIT, 211 (50.0%) to qFIT only, eight (1.9%) to outpatient clinic and one to colonoscopy. Fifteen (3.6%) declined investigation and seven (1.7%) were deemed unfit. We detected 13 cancers (3.1%), similar to the mean cancer detection rate from all referrals in 2017-2019 (3.3%). Compared with the period 1 April-31 May in 2017-2019, we observed a 43% reduction in all primary care referrals (1071 referrals expected reducing to 609).

Conclusion: This COVID-adapted pathway mitigated the adverse effects on diagnostic capacity and detected cancer at the expected rate within those referred. However, the overall reduction in the number of referrals was substantial. The described risk-mitigating measures could be a useful adjunct whilst standard diagnostic services remain constrained due to the ongoing pandemic.

Keywords: COVID-19; colorectal cancer; faecal immunochemical tests; qFIT; triage.

FIGURE 1

NHS Lothian COVID‐adapted colorectal cancer pathway. Patients were triaged by colorectal consultants with information provided from general practice (GP). They proceeded through the pathway in a step‐wise fashion being stratified by quantitative faecal immunochemical test (qFIT) results (CRC, colorectal cancer; CT, computed tomography scan; IDA, iron deficiency anaemia; OPD, outpatient department; USOC, urgent suspected of cancer)

FIGURE 2

Flow of patients through the pathway leading to cancer diagnosis. Patients were diagnosed through a variety of routes, the maximal yield coming from those who had both initial CT and quantitative faecal immunochemical test (qFIT) testing. With 50% being diagnosed from the outpatient clinic, the initial referral examination was deemed to be of great importance

FIGURE 3

Distribution of double quantitative faecal immunochemical test (qFIT) results. Double qFIT testing showed variability of results. Eighty‐four per cent of patients had both results <80 μg/g, 8% had one result <80 μg/g and one >80 μg/g and a further 8% had two results >80 μg/g. There were two cancers diagnosed in those with two qFITs <10 μg/g and one in a patient with two qFITs >400 μg/g (USOC, urgent suspected of cancer)

FIGURE 4

Distribution of quantitative faecal immunochemical test (qFIT) results and overall outcome. The majority of patients had an undetected qFIT result. Despite this three cancers were diagnosed within this group

FIGURE 5

Number of referrals by priority 2017–2019. There was a marked decrease in the total number of referrals during the pandemic, with an increase in the number of ‘urgent suspected of cancer’ referrals (qFIT, quantitative faecal immunochemical test)