Blood test identifies high-risk gastric cancer in underscreened groups

A blood test can screen for gastric adenomas, a pre-cancerous stage of the stomach, and those at high risk for early gastric cancer, according to a study by Korean researchers.

Seoul National University Bundang Hospital (SNUBH) said Wednesday that a team of researchers, led by Professors Kim Na-young and Choi Yong-hoon of the Department of Gastroenterology, analyzed data from more than 2,200 patients who underwent gastroscopy and blood tests at the hospital.

The National Cancer Screening Program, which provides endoscopy every two years for adults 40 and older, is considered to have played a significant role in improving the early detection and treatment of stomach cancer in Korea. However, in recent years, the number of young stomach cancer patients under 40 has been increasing, and many patients over 70 have difficulty undergoing regular gastroscopy due to physical burden, highlighting existing gaps in coverage.

Expanding screening to younger individuals is inefficient due to the low incidence rate, and screening for those over 75 is limited by health status, revealing gaps in the current system. What is needed is a screening strategy that identifies only those at high risk of gastric cancer who need to be tested.

The researchers attempted to find a clue to this in a blood test-based serum pepsinogen kit (GastroPanel).

Stomach cancer usually develops through a process of gradual damage and change to the stomach mucosa over a long period. One of the most common signs of this process is atrophic gastritis.

The researchers used a serum pepsinogen kit that simultaneously tests for helicobacter pylori (H. pylori) infection and serum pepsinogen levels, an indirect indicator of the severity of atrophic gastritis, to identify people at high risk of gastric cancer.

The study's results showed that a decrease in pepsinogen I divided by pepsinogen II (pepsinogen I/II ratio) below 5.3 was associated with a significantly higher risk of gastric adenoma, a precursor to gastric cancer.

In particular, they found that patients with a pepsinogen I/II ratio of 5.3 or less who tested negative for H. pylori infection had a 3.36 times higher risk of developing gastric adenoma and 2.25 times higher risk of gastric cancer than the general population, which could be used as a significant warning sign.

Notably, the researchers did not interpret a negative H. pylori test as a positive factor but rather as a risk factor for atrophic gastritis or severe intestinal epithelialization. This interpretation considers the phenomenon where H. pylori initially damages the gastric mucosa but then dies off in severely compromised conditions.

The study demonstrated the potential of the combined interpretation of serum pepsinogen test and H. pylori infection as a new tool for early gastric cancer screening.

Considering previous studies showing that the combination of pepsinogen II and H. pylori infection can identify high-risk groups of young women with low-grade gastric cancer, it is expected to contribute significantly to filling gaps in the national screening system and designing personalized screening strategies using blood tests, the researchers said.

“It is easy to miss opportunities for early detection of gastric cancer among older adults, who have difficulty undergoing regular endoscopy, or in younger people who are not yet covered by the national screening program,” Professor Kim said. “Our findings provide clinical evidence that a blood test-based screening strategy could be a practical alternative for these patients.”