Background & aims
Initial screening for high-risk population of gastric cancer (GC) is needed in rural areas of large-population countries. This study aims to explore the feasibility of applying noninvasive ultrasonography as an initial screening strategy to improve the early diagnosis and prevention of GC.
Oral contrast-enhanced trans-abdominal ultrasonography (OCTU) was initially applied to screen around 15,000 residents from 24 different rural villages of Changxing Island in Shanghai, China, facilitating the identification of high-risk population for further endoscopy examination.
176 subjects (1.18 %) were initially identified with gastric diseases using OCTU while 14,787 ones (98.93 %) were normal with negative results. 145 out of 176 individuals (82.39 %) took further endoscopy examination, and 16 were diagnosed with GC with biopsy examination, with 9 of them at the early stage. We followed up with the Center for Disease Control and Prevention, and identified another 6 GC cases occurred within one year among OCTU-negative population, serving as an adjustment factor for sensitivity analysis. As a result, with a total of 22 GC cases included in this cohort, the positive predictive rate, the negative predictive value, sensitivity, and specificity were 9.09％, 99.96 %, 75.5 %, and 98.93 %, respectively.
OCTU is feasible, non-invasive, low-cost, and widely acceptable in rural area, thus we proposed that OCTU is practicable to serve as a supplementary screening method to improve the early detection of GC in rural area of China and other developing countries with large population.
- • Initial screening for high-risk population of gastric cancer (GC) is needed in rural areas of large-population countries.
- • This is a prospective study with ~15,000 asymptomatic residents from 24 rural villages in Changxing Island, Shanghai, China.
- • We evaluated the performance of oral contrast-enhanced trans-abdominal ultrasonography (OCTU) in screening high-risk GC.
- • OCTU could serve as an effective initial screening method of GC or supplement to the current risk stratification rule.
Gastric cancer (GC) remains a major challenge to the public health with the fifth incidence and third mortality worldwide, according to the global cancer statistics in 2018 . However, approximately half of the world’s incident and mortality cases of GC occur in China. In 2015, the estimated GC incidence rate was 6.79 per 100,000 and estimated mortality rate was 4.98 per 100,000, roughly 1364 deaths per day. Moreover, the 5-year survival rate of GC was low in China because more than 80 % of patients were diagnosed at the advanced stages due to the absence of specific symptoms . Thus, early diagnosis and treatment are very crucial to reduce the mortality of GC. However, the early detection relies on opportunistic screening only . Since 2008, the screening programs for early detection of upper gastrointestinal diseases have been launched in selected high-risk areas of China, including the national Upper Gastrointestinal Cancer Early Detection (UGCED) program and Cancer Screening Program in Urban China (CanSPUC) .
Currently, gastroscopy with sampling of gastric biopsies for histopathological examination is the gold standard for GC diagnosis . The early detection of GC has been over 50 % in the United States and East Asian countries (e.g., Japan and Korea) with government-sponsored screening program by barium fluorography or endoscopy . Compared to these countries, GC patients in China had larger tumors, a later stage at presentation, and worse outcome . Although there is no nationwide screening program of GC, the current guideline recommends the screening beginning at age 40 years for the high-risk population. However, more than 45 % of the population in China is aged over 40 years, it is not feasible to offer gastroscopy screening to all in this population considering the high cost as well as limited clinical resources of technicians and gastroscopy equipments . Moreover, uncomfortable feelings and even fear of gastroscopy make it difficult to be accepted in a wide population, in particular for elderly people in rural area who did not have public health education of early diagnosis and prevention of diseases. Thus, considering the large population in China and the necessity of wide acceptability, it is better to provide a non-invasive screening strategy that could be accurate, reliable, cost-effective, and publicly acceptable in a wide population.