Impact of COVID-19 pandemic on short-term outcomes after low anterior resection in patients with rectal cancer: Analysis of data from the Japanese National Clinical Database

Aim: The Coronavirus Disease 2019 (COVID-19) pandemic affected the allocation of various medical resources to several areas, including intensive care units (ICUs). However, currently, its impact on the short-term postoperative outcomes of gastrointestinal cancer surgeries remains unclear. We aimed to evaluate the impact of the pandemic on the incidence of complications occurring after low anterior resection in patients with rectal cancer in Japan. Methods: Data from the Japanese National Clinical Database between 2018 and 2021 were retrospectively examined. The primary outcome of the study was the postoperative morbidity and mortality rates before and after COVID-19 pandemic. Moreover, the postoperative ICU admission rate was assessed. Morbidity and mortality rates were also assessed using a standardized morbidity/mortality ratio (SMR, the ratio of the actual number of incidences to the expected number of incidences calculated by the risk calculator). Results: This study included 74 181 patients, including 43 663 (58.9%) from COVID-19 epidemic areas. The mean actual incidences of anastomotic leakage (AL) and pneumonia during the study period were 9.2% and 0.9%, respectively. The SMRs of these complications did not increase during the pandemic but those of AL declined gradually. The mean 30-day mortality and operative mortality rates were 0.3% and 0.5%, respectively. Moreover, SMRs did not change significantly in the pandemic or regional epidemic status. The ICU admission rate temporarily decreased, especially in the epidemic areas. Conclusion: Although the pandemic temporarily decreased the ICU admission rate, its impact on short-term outcomes following low anterior resection in patients with rectal cancer was insignificant in Japan.