The Statuses of Colonoscopy and Colorectal Cancer According to Big National Disasters Such as COVID-19 and Earthquake.

[OBJECTIVES] Sudden decrease of colonoscopy (CS) numbers can be related to the status of colorectal cancer (CRC). This study aimed to evaluate the statuses of CS and CRC according to big national disasters such as the Great East Japan Earthquake in 2011 and the COVID-19 epidemic in 2020.

[METHODS] We retrospectively used the JMDC database of commercially anonymized health insurance claims data including 4,601,921 patients ≥ 50 years old from January 2010 to December 2022 (without health checkups of CS and esophagogastroduodenoscopy [EGD]). The main outcome was a yearly analysis for 2010-2022 about (1) rate of CS, (2) rate of CRC and rate of CRC per CS compared to those of EGD and gastric cancer (GC), and (3) rate of surgery for CRC. Additionally, a monthly analysis for those rates was performed to examine the detailed effect of the earthquake and COVID-19 infection.

[RESULTS] The rates of CS and EGD in 2010/2011/2012 were 3.10%/3.41%/3.42% and 6.94%/6.96%/7.00% and those in 2019/2020/2021 were 5.20%/4.74%/5.37% and 7.47%/6.42%/6.84%, respectively. The rates of CS and EGD decreased not in 2011 (The earthquake) but in 2020 (COVID-19). The rates of CRC and GC in 2019/2020/2021 were 0.199%/0.175%/0.195% and 0.110%/0.096%/0.099%, and both showed a decrease in 2020. Monthly analysis showed that the rate of CRC per CS had an increase in April and May in 2020 compared to that in March of 2020. The rate of surgery for CRC in 2019/2020/2021 was 0.087%/0.079%/0.087% with a deficiency in 2020.

[CONCLUSIONS] The rates of CS and CRC decreased in 2020 due to COVID-19.