BACKGROUND/AIMS: Despite of the coronavirus disease 2019 (COVID-19) pandemic, there is little data regarding its impact on colorectal cancer (CRC)-related clinical practice. This study aimed to assess the changes in its impact during the COVID-19 pandemic. METHODS: This was a retrospective national population-based study using the Health Insurance Review and Assessment database from January 2019 to December 2021. The number of patients in 2020 and 2021 was compared with those in 2019 for the diagnostic and therapeutic colonoscopy, CRC-related operation, and any treatment for CRC. RESULTS: The annual number of patients undergoing diagnostic colonoscopies decreased by 6.9% in 2020 but increased 8.1% in 2021, compared to those in 2019
number of patients undergoing therapeutic colonoscopies increased by 6.0% and 37.7% in 2020 and 2021, respectively
number of patients operated for CRC decreased by 4.2% in 2020 and increased by 2.3% in 2021. The number of patients treated for CRC decreased by 2.8% in 2020 and increased by 4.4% in 2021. Diagnostic and therapeutic colonoscopies and any CRC-related treatment decreased by 43.8%, 37.5%, and 11.3% in March 2020, during the first surge of COVID-19, but increased by 26.0%, 58.1%, and 9.5% in June 2021, respectively. CRC-related operations decreased by 24.1% in April 2020 and increased by 12.6% in August 2021. CONCLUSIONS: Negative impact of the COVID-19 pandemic on clinical practices related to CRC completely recovered within second year. It could be considered for the development of an optimal strategy on CRC management in response to the pandemic-driven crisis.