Real-world evidence of safety and influence for lung cancer surgery under COVID-19 pandemic in Japan.

Background: The COVID-19 pandemic has affected the clinical practice of lung cancer surgery in Japan, but few studies have revealed the real situation of surgical practice for lung cancer in this country. This latest information will help us to decide the future direction of lung cancer surgery under pandemic circumstances. Methods: We collected data from patients with primary lung cancer who underwent thoracic surgery between 2018 and 2021. To investigate the impact of the COVID-19 pandemic on lung cancer surgery, we compared between 2018-2019 (prepandemic group) and 2020-2021 (pandemic group) in the respect of patient characteristics, pathological findings, and short-term outcome after lung cancer resection by Mann-Whitney and Fisher's exact tests. Moreover, the monthly number of surgeries for lung cancer in our institution during 2020-2021 was compared with the number of newly diagnosed COVID-19 patients in Japan by Spearman correlation analysis. Results: From 2018 through 2021, 936 patients with primary lung cancer underwent surgical intervention in our institute and were included in this study. The number of surgeries did not decrease in the pandemic group (n=443) compared with that in the prepandemic group (n=493). Tumor and invasive size in stage I which was measured by pathologist were significantly larger in the pandemic group than in the prepandemic group (tumor size: P=0.031, invasive size: P<0.001). In terms of postoperative short-term outcome, the median hospital stay was 6 days, 30-day mortality was 2, and morbidity was around 20% in both groups. Only one patient suffered from COVID-19 infection 5 months after right upper lobectomy. An increased ratio of newly diagnosed COVID-19 cases in Japan was negatively correlated with the number of surgeries for lung cancer in our institution in the next month (r=-0.393, P=0.007), although there was no correlation in the present or the month after next. Conclusions: Even during the COVID-19 pandemic period, lung cancer surgery could be performed safely and in a sustainable manner. However, pathological findings of lung cancer tended to be progressive in early-stage lung cancer.