Table 1.

The effect of COVID-19 on the diagnosis of gastric cancer

First author	Country	Study design or source of the data	Quality	Main result
Buscarini [4]	Italy	Web based survey	Good	Compared to 2019, in 2020, the diagnosis of patients with gastric cancer decreased by 15.9% due to the decrease in the volume of diagnostic services
De Vincentiis [15]	Italy		Fair	The diagnosis of gastric cancer in 2020 has decreased by 10% compared to 2018 and 2019
Wheaton [5]	The UK	Retrospective study	Fair	During the COVID-19 epidemic, the endoscopic volume decreased by 88% and cancer diagnosis rate decreased by 66%. This reduction depends on the duration and severity of the restrictions
Brito [2]	Portugal	Retrospective study	Good	In 2020, most patients were referred from the emergency department, indicating a delay in requesting clinical attention
Manes [19]	Italy	Retrospective study	Fair	The number of rapid endoscopic procedures has decreased by 53.6% compared to 2019 and 2020 One of the reasons for this decrease was the perception of patients and physicians of the risk of COVID-19
Lantinga [17]	Netherlands	Retrospectively analyzed endoscopies	Good	By 2020, endoscopy has declined, which gastroscopy has decreased by 57%. During corona virus limitations, the diagnosis of cancer has been significantly reduced. But after lifting the restrictions, the endoscopy performance returned to normal The endoscopies were postponed or canceled
Lui [18]	China	A population-based study	Good	The average number of stomach cancers diagnosed each week decreased by 46.2% The results of linear regression model showed that there is a relationship between the number of gastric cancers and endoscopy performing
Huang [16]	China	A retrospective cohort study	Good	Endoscopy decreased by 30.63% during the epidemic compared to the same period last year. The rate of gastric cancer diagnosed has increased in endoscopies
Armellini [28]	Italy	Retrospectively analyzed endoscopies	Good	In the study of 847 patients from 13 centers in Italy for endoscopy. 29.4% of patients did not have an endoscopy due to fear of becoming infected with COVID-19 virus
Cai [12]	China	Retrospectively study	Good	The results showed that 2 months delay leads to advanced lymph node metastasis and deterioration of the patient's nutritional status and is effective in disease mortality
Giuliani [29]	Italy	Retrospective analysis	Good	The results of a study on 29 patients showed a 14.5% reduction in diagnostic tests. A 76% decline in the registration of new patients was observed during the restriction time