Gastrointestinal Cancer Stage at Diagnosis Before and During the COVID-19 Pandemic in Japan

IMPORTANCE The COVID-19 pandemic has delayed medical consultations, possibly leading to the diagnosis of gastrointestinal cancer at advanced stages. OBJECTIVE To evaluate stage at diagnosis among patients with gastrointestinal cancer in Japan before and during the COVID-19 pandemic. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort study included patients in a hospital-based cancer registry who were diagnosed with gastrointestinal cancer (ie, esophageal, gastric, colorectal, pancreatic, liver, and biliary tract cancers) between January 2016 and December 2020 at 2 tertiary Japanese hospitals. EXPOSURES The pre-COVID-19 period was defined as January 2017 to February 2020, and the COVID-19 period was defined as March 2020 to December 2020. MAIN OUTCOME AND MEASURE Monthly numbers of patients with newly diagnosed cancer were aggregated, classified by stage, and compared. RESULTS The study evaluated 5167 patients, including 4218 patients (2825 [67.0%] men; mean [SD] age, 71.3 [10.9] years) in the pre-COVID-19 period and 949 patients (607 [64.0%] men; mean [SD] age, 71.8 [10.7] years) in the COVID-19 period. Comparing the pre-COVID-19 period with the COVID-19 period, significant decreases were observed in the mean (SD) number of patients with newly diagnosed gastric cancer (30.63 [6.62] patients/month vs 22.40 [5.85] patients/month; -26.87% change; P<.001) and colorectal cancer (41.61 [6.81] patients/month vs 36.00 [6.72] patients/month; -13.47% change; P=.03). Significant decreases were also observed in the mean (SD) number of cases of stage I gastric cancer (21.55 [5.66] cases/month vs 13.90 [5.99] cases/month; -35.51% change; P<.001), stage 0 colorectal cancer (10.58 [3.36] cases/month vs 7.10 [4.10] cases/month; -32.89% change; P=.008), and stage I colorectal cancer (10.16 [3.14] cases/month vs 6.70 [2.91] cases/month; -34.04% change; P=.003). No significant increases were observed for esophageal, gastric, pancreatic, liver, or biliary tract cancers. A significant decrease was observed in the mean (SD) number of cases per month of stage II colorectal cancer (7.42 [3.06] cases/month vs 4.80 [1.75] cases/month; -35.32% change; P=.01); a significant increase was observed for the mean (SD) number of cases per month of stage III colorectal cancer (7.18 [2.85] cases/month vs 12.10 [2.42] cases/month; 68.42% change; P <.001). CONCLUSIONS AND RELEVANCE In this cohort study of patients in a hospital-based cancer registry form 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.

Automated summary

This study in Japan found that during the COVID-19 pandemic, significantly fewer patients were diagnosed with stage I gastric and colorectal cancers, suggesting a decrease in screening-detected cancers and potential diagnoses at more advanced stages.