Rates of Diagnosis of Gastrointestinal Cancers—and Stage at Diagnosis—Before and During the COVID-19 Pandemic in Japan

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In a study reported in JAMA Network Open, Kuzuu et al found that the COVID-19 pandemic in Japan was associated with reduced rates of new diagnoses, as well as reduced rates of diagnosis at earlier stages, for some gastrointestinal cancers.

Study Details

The retrospective cohort study included data from patients in a hospital-based cancer registry diagnosed with gastrointestinal cancers (esophageal, gastric, colorectal, pancreatic, liver, and biliary tract) at two tertiary Japanese hospitals. The analysis included 5,167 patients, including 4,218 diagnosed during the pre–COVID-19 period of January 2017 to February 2020, and 949 diagnosed during the COVID-19 period of March 2020 to December 2020.

Key Findings

For the COVID-19 vs pre–COVID-19 periods, significant reductions in mean newly diagnosed cases per month were observed for gastric cancer (30.63 vs 22.40, –26.87% change, P < .001) and colorectal cancer (41.61 vs 36.00, –13.47% change, P = .03). No significant differences were observed for pancreatic cancer (14.00 vs 14.10, P = .93), esophageal cancer (8.82 vs 8.70, P = .91), hepatocellular carcinoma (8.89 vs 7.50, P = .20), or biliary tract cancer (7.05 vs 6.20, P = .42).  

In the COVID-19 period, significant decreases were observed in mean number of cases diagnosed per month for stage I gastric cancer (21.55 vs 13.90, –35.51% change, P < .001), stage 0 colorectal cancer (10.58 vs 7.10, –32.89% change, P = .008), stage I colorectal cancer (10.16 vs 6.70, –34.04% change, P = .003), and stage II colorectal cancer (7.42 vs 4.80, –35.32% change, P = .01), whereas there was a significant increase for stage III colorectal cancer (7.18 vs 12.10, 68.42% change, P < .001).

During the COVID-19 period, nonsignificant numerically greater rates of diagnoses per month were observed for stage IV gastric cancer, stage III or IV pancreatic cancer, stage III or IV esophageal cancer, stage III or IV hepatocellular carcinoma, and stage II biliary tract cancer.

The investigators concluded, “In this cohort study of patients in a hospital-based cancer registry from Japan, significantly fewer patients were diagnosed with stage I gastric and colorectal cancers during the COVID-19 pandemic. Thus, the number of screening-detected cancers might have decreased, and colorectal cancer may have been diagnosed at more advanced stages.”

Takuma Higurashi, MD, PhD, of the Department of Gastroenterology and Hepatology, Yokohama City University School of Medicine, is the corresponding author for the JAMA Network Open article.

Disclosure: For full disclosures of the study authors, visit

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