Impacts of COVID-19 pandemic on short-term outcomes of low anterior resection performed in hospitals with different surgical volumes.

Aim: To evaluate the impact of the coronavirus disease (COVID-19) pandemic on short-term outcomes of low anterior resection (LAR) across hospitals classified by surgical volume. Methods: Data of patients who underwent elective LAR for rectal cancer between 2018 and 2022 were obtained from the National Clinical Database of Japan. Hospitals were categorized into high-, medium-, and low-volume groups. Each group was constituted to represent approximately one-third of all surgeries performed between 2018 and 2019. The standardized morbidity/mortality ratios (SMRs) of Clavien-Dindo grade ≥3 (CD ≥ 3) complications were the primary endpoint. The secondary endpoints included anastomotic leakage, pneumonia, and surgical mortality. Results: This study analyzed 91 800 cases of elective LAR, with 10.5% experiencing CD ≥ 3 complications, 8.8% anastomotic leakage, 0.9% pneumonia, and 0.5% surgical mortality. Despite COVID-19, SMRs of CD ≥ 3 complications decreased from 2018 to 2022 across all groups. However, increases in the rates and SMRs of CD ≥ 3 complications were observed in low-volume hospitals around mid-2020, followed by a decline. Anastomotic leakage showed similar trends. The rates and SMRs of pneumonia and surgical mortality remained unchanged. Notably, anastomotic leakage rates were 7.6%, 8.9%, and 10.0% in high-, medium-, and low-volume hospitals, respectively, indicating superior outcomes in high-volume hospitals. Conclusion: Early COVID-19 waves may have disproportionately affected low-volume hospitals. However, the decline in SMRs of CD ≥ 3 complications from 2018 to 2022 across all three groups suggests the robustness and resilience of surgical services for rectal cancer in Japan. The potential disparity in short-term outcomes among hospitals is a new concern.