The impact of early-stage COVID-19 pandemic on the diagnosis and treatment of gastric cancer: A cross-sectional study using a large-scale cancer registry in Hiroshima, Japan

Background: After the confirmation of coronavirus infection in Japan, a behavioral change caused people and physicians to refrain from visiting hospitals or undergoing examinations. This study aimed to assess how the trend of diagnosis in gastric cancers changed, and how it affected the therapeutic strategies and the interval from diagnosis to treatment during the COVID-19 pandemic. Methods: We use 15 cancer-designated hospitals' registries in Hiroshima, Japan. The target period was March to December 2020, and the same period in 2019 was set as the control period. The monthly mean of diagnoses and the interval from diagnosis to treatment were compared overall and separately by age, treatment procedure, diagnostic process, and clinical stage. Result: In 2020, the monthly mean (standard deviation [SD]) of patients was 192.2 (29.9), a significant 20.1% decrease from 240.7 (20.7) in 2019 due to older age and curative treatment groups. By reason for performing endoscopy, the change rate in cancer screening, endoscopic follow-up, and symptomatic status were -27.0%, -18.0%, and -17.3%, respectively. Meanwhile, the interval (days) from diagnosis to treatment (SD) was 37.8 (26.5) in 2020, significantly shorter than 46 (31.5) in 2019. Conclusion: From 2019 to 2020, we observed a significant decrease in the diagnosis of curable early-stage gastric cancer and treatments, although the interval from diagnosis to treatment decreased. This study suggests that cancer screening played a significant role in the decline in cancer diagnosis that occurred during the COVID-19 pandemic. Even under COVID-19 pandemic conditions, there should be an awareness of cancer screening and endoscopic follow-up.