Lung cancer screening has been a success story in high-income countries, leading to a shift in diagnoses to earlier stages and a reduction in mortality among eligible groups.
A new report shows that middle- and low-income countries are being left out. “We do have good screening programs and some national ones, even in smaller European countries and in Canada, but either at all or not implemented nationwide. This is a huge problem in the world,” said Milena Cavic, PhD, who presented the interim results on behalf of the diagnostics working group of the International Association for the Study of Lung Cancer early detection and screening committee at a press conference on Aug. 7 at the World Conference on Lung Cancer. Dr. Cavic is a senior research associate at the Institute for Oncology and Radiology of Serbia in Belgrade.
“It’s definitely a work in progress, and it’s also about raising awareness of the problem. In several parts of Asia, in Taiwan, in Korea, smoking is not the major, or at least, not the only reason for getting lung cancer. The other reasons are family history and also environmental factors like cooking fires, etc. So, the criteria we have for screening in Western countries are not one to one implementable in these countries,” said Rudolf Huber, MD, PhD, a respiratory physician at Ludwig Maximilian University of Munich and a coauthor of the report.
The report also pointed out the lack of recommendations for lung cancer screening in middle- and low-income countries. One approach would be to produce recommendations for countries with similar infrastructures and health resources, as well as primary risk factors such as smoking or cooking fires. “We have to adapt it to the various situations,” said Dr. Huber.
Another possibility is to rework existing recommendations for high income countries to adapt them to low- and middle-income countries. In the coming year, the working group will conduct a modeling study of Serbia, China, South Africa, and Columbia. It will look at population-specific and geographic factors from each country to produce country-specific models. “It will be interesting to see if these models will give us new recommendations for countries like this. So we can derive something from the high-income countries, but it will need to be adapted very, very much,” said Dr. Cavic.
The report highlighted some of the disparities between countries. CT scanners are far more common in high-income countries. Japan leads the way at 111.5 per million residents, followed by Australia at 70.2, Iceland at 47.6, and the United States at 44.9. At the other end is Columbia with 1.3, which trails Mexico at 5.9, Hungary at 9.4, and the United Kingdom at 9.5. However, the authors point out that there is no consensus on the optimum number of CT scanners per capita, since too few can lead to lack of access and too many can result in overuse. In fact, the greatest number of CT scans performed per capita was in the United States (278.5 per million), followed by Iceland (234.4), Japan (230.8), and Korea (228.1).
Lung cancer screening can be at odds with other health priorities, especially in low-income countries. These can include HIV, tuberculosis, and granulomatous diseases. But that could also provide an opportunity, according to Dr. Huber. “For example, in South Africa, tuberculosis programs are done by chest x-ray. We now have data that [allows us to] detect nodules by artificial intelligence, so one of the things we are thinking about is whether we could even use chest x-ray to get an earlier detection. At the end, it may be that in some countries it’s possible to do the classical CT screening, while in other countries we have to adapt to other options – probably chest x-ray using artificial intelligence or computer-aided diagnosis. And, then a consequent program for following up and managing the incidentally diagnosed nodules.”
The group is hoping to explore the environmental factors that could affect lung cancer risk in middle- and low-income countries. That is difficult to do, however, because smoking data can be hard to come by in many countries, and there is general uncertainty about what other risk factors may exist, though air pollution is a clear suspect. “It is something we are hoping to focus on in the future because there is a subgroup of individuals without a smoking history who are at high risk. It would be really good to find this high-risk population that should actually be screened in the future,” Dr. Cavic said.
Some countries have no data on lung cancer screening. For example, only South Africa is represented from Africa, and data is missing from many countries in Asia. The diagnostics working group of the IASLC early detection and screening committee has created a survey to gather information on the availability of lung cancer screening and its effect on diagnosis and treatment in countries throughout the world.
Dr. Cavic and Dr. Huber reported no relevant financial disclosures. The meeting was sponsored by the IASLC.