The impact of delaying colonoscopies during the COVID-19 pandemic on colorectal cancer detection and prevention

PURPOSE: The COVID-19 pandemic resulted in a partial to total shutdown of endoscopy in many healthcare centers. This study aims to quantify the impact of the reduction in colonoscopies on colorectal cancer (CRC) detection and screening. METHODS: After institutional ethics board approval, the endoscopy database at an academic tertiary-care center in Montreal, Canada, was searched for all colonoscopies performed from during the first wave locally (March–June 2020), and during the ramp up period where endoscopy service resumed (July to August 2020). We compared these periods to the same periods in 2019, the pre-pandemic periods. The indications, CRC and adenoma detection rates, as well as the prioritization of urgent procedures were compared. RESULTS: In the first wave, only 462 colonoscopies were performed, compared to 2515 in the same period in 2019, an 82% reduction. The ramp up period saw 843 colonoscopies performed compared to 1328 in 2019, a 35% reduction. Urgent and inpatient colonoscopies numbers increased (324 (24.8%) vs. 220 (5.7%)) while surveillance and high-risk screening colonoscopies fell (376 (28.8%) vs 1869 (48.6%)). Emergency access to colonoscopy was preserved with a median time to endoscopy of < 1 day (IQR 0,1) in both pandemic periods. During the pandemic periods, there was an absolute reduction in CRC diagnosis of 28, despite the CRC detection per colonoscopy rate increasing slightly in the first wave from 1.7% (44) to 3.9% (18), and in the ramp up period from 2.5% (33) to 3.6% (31). The rate of adenoma detection per colonoscopy did not increase significantly between the pre- and pandemic periods, resulting in reduction in adenoma removal in 723 patients. DISCUSSION: The restriction of access to colonoscopy resulted in a significant reduction in screening and surveillance of high-risk patients, adenomas removed, and CRCs diagnosed. Clinicians and patients will face the oncologic ramifications this the coming years. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00464-022-09211-z.