Exploring the cost-effectiveness of Helicobacter pylori screening to prevent gastric cancer in China in anticipation of clinical trial results

Helicobacter pylori (H. pylori) infection is classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and is associated with an estimated 65–80% of gastric cancer.1-3 Gastric cancer is the second leading cause of cancer-related deaths worldwide and a major public health problem with over 40% of all cases occurring in China. On the basis of current age-specific rates of gastric cancer and projected demographic changes, the annual number of expected cases in the country alone will increase from 393,000 in 2002 to 795,700 in 2030.4 Over the past 30 years, the understanding of gastric carcinogenesis has advanced. Specifically, the role of H. pylori and the development of gastric cancer through a series of precancerous lesions have shifted the focus of gastric cancer research from palliative strategies to the development of preventive strategies, including screening for H. pylori, especially in China where nearly 60% are infected, the majority of whom are asymptomatic.5,6 Although the infection is relatively easy to detect and treat with a non-invasive diagnostic test and course of antibiotics, the effectiveness of treatment to prevent gastric cancer is uncertain and screening thus far has not been recommended. Ideally, the strongest evidence would come from randomized controlled trials that use gastric cancer incidence as the primary outcome. Several clinical trials are underway7 and results from the first of such studies showed that after 7.5 years, treatment for H. pylori reduces cancer incidence among individuals without preexisting precancerous lesions, defined as atrophy, intestinal metaplasia and dysplasia, at time of treatment.8 Studies measuring intermediate outcomes also provide indirect support for a benefit on cancer risk via reduced progression of precancerous lesions to cancer. To estimate the public health benefits of a H. pylori screening program, several factors must be considered: the underlying natural history of H. pylori-associated disease; the heterogeneity of risk conferred by gender, age and country; the effectiveness of treatment for H. pylori in interrupting the pathway to cancer; and the feasibility of implementing a secondary prevention program at the population level. As no single empirical study can evaluate all possible H. pylori screening and treatment strategies, by integrating the best biologic, epidemiologic and economic data, mathematical simulation models can assist in decision making by leveraging available data on intermediate outcomes to estimate the avertable burden of disease expected with different strategies, identify influential factors for which better empirical data would be most valuable, and provide insight into the potential cost-effectiveness of different strategies.9 The feasibility of introducing a new public health intervention in any country, especially one that is resource-constrained, is complex given competing health priorities. Cost-effectiveness analysis when used in conjunction with other equally important information on affordability, political will and cultural preferences and distributional and equity considerations can provide useful information to decision makers considering alternative public health interventions and policies. By quantifying the relative health and economic consequences of one investment compared with another, cost-effectiveness analyses provide information on the investment’s “value for money.” To inform the dialogue and debate about the potential value of gastric cancer prevention programs, we explored the health benefits and economic consequences associated with screening for H. pylori in China.