Cost-Effectiveness of Population Screening Strategies for Gastric Cancer in India: A Markov Model Calibrated to High- and Low-Incidence Districts

Gastric cancer, a disease that begins in the stomach, remains a leading cause of death worldwide, yet its impact is not felt equally across the globe. In some places, it is a common threat; in others, it is rare. This uneven distribution creates a difficult question for public health officials: should a country screen its entire population for this disease? Screening involves checking healthy people for early signs of illness before they feel sick, with the hope of catching the disease when it is easier to treat. However, these programs are expensive and require significant resources. If a disease is rare, the cost of testing millions of people to find a handful of cases can outweigh the benefits, draining funds that could be used for other life-saving treatments. In India, the situation is particularly complex. While the country has organized screening programs for breast, cervical, and oral cancers, it has no such plan for gastric cancer. Furthermore, the risk of developing this cancer varies wildly across the country, with some regions seeing rates seven times higher than others. This geographic patchwork makes it impossible to apply a single rule to the entire nation, leaving policymakers without clear guidance on whether a national screening effort would be a wise investment.

To answer this question, researchers built a detailed computer simulation to act as a virtual laboratory. They created a model that followed a hypothetical group of 100,000 adults, starting at age 40 and tracking them through the rest of their lives. The model was designed to mimic the real-world progression of gastric cancer, moving from a healthy state to pre-cancerous changes, then to early-stage cancer, and finally to advanced disease or death. The researchers calibrated this simulation using real data from two very different districts in India: one with a high rate of cancer and another with a low rate. This allowed them to test four different approaches. The first was doing nothing, which represents the current reality where cancer is only found when a patient feels sick. The second involved testing for a specific bacteria called Helicobacter pylori every five years and treating those who tested positive to prevent cancer from forming. The third strategy used a blood test every three years to look for chemical markers, sending positive results for further examination. The fourth option was the most direct: performing an internal camera examination of the stomach, known as an endoscopy, on everyone every five years.

The results of this simulation were clear and consistent across both high-risk and low-risk scenarios. In the district with the highest cancer rates, the screening strategies did succeed in saving lives. The camera examination, or endoscopy, prevented the most deaths and found the most cancers at an early, treatable stage. However, this success came at a steep price. The cost to save a single year of healthy life was far higher than what the Indian health system typically considers a good value. Even the strategy of testing for the bacteria, which was the most affordable option, still cost significantly more than the established threshold for a worthwhile health investment. When the researchers applied the same logic to the low-incidence district, the situation became even less favorable. Because the disease was so rare there, the cost to find and treat each case skyrocketed, making the screening programs even less efficient. In fact, the simulation showed that for any of these strategies to become cost-effective, the rate of cancer in the population would need to be much higher than what is currently observed anywhere in India.

The study also revealed that not all screening methods are created equal. One approach, which used a blood test to screen for chemical markers, performed poorly in both scenarios. It cost more than the direct camera examination while saving far fewer lives, effectively wasting resources. This happened because the blood test was not sensitive enough to catch many cases, yet it still sent a large number of people for expensive follow-up procedures. In contrast, the strategy of testing for and treating the bacteria was more efficient because it stopped the disease from developing in the first place, rather than just finding it earlier. Yet, even this preventative approach did not meet the cost-effectiveness standards required for a national program. The researchers found that the deciding factor was not how good the tests were, but simply how common the disease was in the background population. When a disease is rare, the math of screening rarely works in its favor.

These findings suggest that a blanket policy of screening every adult in India for gastric cancer would not be a smart use of limited medical funds. The simulation indicates that such a program would not provide enough value for the money spent, even in the regions where the disease is most common. Instead of a universal approach, the evidence points toward a more targeted strategy. The researchers propose that future efforts should focus on identifying specific subgroups of people who are at genuinely high risk, perhaps due to their location, family history, or other factors, and directing resources only toward them. Until more specific data becomes available regarding how well these tests work in the Indian population and the true costs of treatment, the most prudent path is to avoid a nationwide rollout. The study concludes that while the idea of catching cancer early is sound, the economic reality in India currently argues against a mass screening program, urging a shift toward precision rather than breadth.