麻豆传媒

During the COVID-19 pandemic in Japan, fewer cases of certain gastrointestinal cancers were detected overall, while more colorectal cancers (CRCs) were diagnosed at a later stage, a hospital-based cancer registry found.

In an analysis of more than 5,000 patients diagnosed from 2017 through the end of 2020, a 26.9% decline was observed for gastric cancer diagnoses during the pandemic compared with years prior (22.4 vs 30.6 cases per month, respectively; P<0.001), and a 13.5% decline was seen for colorectal cancer diagnoses (36.0 vs 41.6; P=0.030), reported Takuma Higurashi, MD, PhD, of the Yokohama City University School of Medicine in Japan, and colleagues.

The average number of monthly cases for early-stage gastric cancer and CRC dropped by 33-35% during versus before the pandemic, respectively:

• Stage I gastric cancer: 13.9 vs 21.6 cases per month (P<0.001)
• Stage 0 CRC: 7.1 vs 10.6 (P=0.008)
• Stage I CRC: 6.7 vs 10.2 (P=0.003)
• Stage II CRC: 4.8 vs 7.4 (P=0.010)

Meanwhile, average monthly cases for stage III CRC increased by a significant 68.4% during the pandemic (12.1 vs 7.2 before; P<0.001), according to the findings in .

"Colorectal cancer is generally recognized as a slow-growing cancer, with prolonged times to doubling and progression, and years are typically needed for adenomas to become cancerous," the authors wrote. "However, the rate of progression is less clear for more advanced colorectal cancer."

Researchers predicted that the number of new cancer diagnoses would decrease due to the nationwide COVID-19 lockdown, Higurashi told 麻豆传媒. "We showed the actual number of diagnosed cancer patients in 2020 and proved that prediction was correct."

"In gastric and colorectal cancer, early-stage cancers are often detected by medical examinations, and the lockdown led to a decrease in the number of diagnoses as a result of fewer medical examinations," Higurashi said. "In the U.S., there were more COVID deaths than in Japan and the impact on medical care was greater, so I expect we will see similar results."

New cases of pancreatic, esophageal, hepatic, and biliary cancers did not decrease, according to the study.

"We guess that the reason for this is that these cancers are often detected in symptomatic cases, so the number of patients diagnosed did not change before and after COVID," said Higurashi.

For their study, the researchers evaluated 5,167 patients diagnosed with gastrointestinal cancers at two Japanese hospitals during (n=949; March to December 2020) and before the pandemic (n=4,218; January 2017 to February 2020).

About two-thirds of the patients were men, and the average age was 71-72 years. In both the pre-pandemic and pandemic periods, the most common cancers were CRC (37.5% and 37.9% of cases, respectively), gastric cancer (27.6% and 23.6%), and pancreatic cancer (12.6% and 14.9% of cases).

The analysis had several limitations, the researchers acknowledged, including that the sample only included two Japanese medical centers. Additional outcomes such as pandemic-related survival also were not evaluated.

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