Health Europa explored with United European Gastroenterology about the efforts regarding gastric cancer treatment, understanding and prevention.
Organised by the Healthy Stomach Initiative (HSI), 2 October marked the first-ever World Stomach Day, an international initiative dedicated to raising awareness of and boosting research into one of the body’s most important organs. A key part of the digestive system, the stomach is vulnerable to a wide range of diseases, including gastroenteritis, functional dyspepsia and gastric cancer, the latter of which is responsible for close to 60,000 deaths every year in the EU. Gastric cancer treatment is something that is still being explored, Health Europa spoke to UEG’s Dr Tamara Matysiak-Budnik to find out more about this devastating disease and the efforts taking place in Europe and elsewhere to improve early detection, prevent its development, and extend survival.
What progress has been made to aid the early detection of gastric cancer?
The early detection of superficial lesions can be achieved by endoscopy. There are two important things to consider within this:
- Who to examine: Obviously we cannot examine everyone, so we must target
- How to examine: The stomach is a relatively large organ and it must be examined centimetre by centimetre, so it’s important to consider the quality of the procedure and of the instrument or endoscope used.
Besides that, it is important to remember that early lesions are usually asymptomatic, i.e. gastric cancer does not display any symptoms in its early stages. By the time someone has the condition, it is already too late, the lesions are too big and gastric cancer treatment is less effective. The luckiest patients are therefore the ones with heartburn or other symptoms, not related to the lesions, who by chance have an endoscopy.
That’s why it is important to endoscope people who are at risk because they live in areas of high incidence. For instance, in Asian countries such as Japan, Korea and China there is a very high incidence of gastric cancer and so there are very good national screening programmes in place. Japan asks everyone over 40 to attend endoscopic screening, and as a result it has an early detection rate of about 70%, which is tremendous progress.
Of course, in Europe the incidence of gastric cancer if relatively low, and implementing a national screening programme would not be justified. We have, however, made some progress in early detection over the last 20 years or so – from roughly 4% of early superficial lesions to perhaps 10% or 12% today. Nonetheless, a lot remains to be done.
What greater efforts could be made to prevent the development of gastric cancer?
Several factors are involved the development of gastric carcinogenesis, the most important of which is infection with the bacterium Helicobacter pylori. At least 90% of gastric cancer cases are related to H. pylori, which makes the eradication of this bacterium central to prevention efforts.
Gastric cancer develops over several years, decades even, as the result of a cascade of events. With the exception of hereditary diffuse gastric cancer, which is very rare, it begins with an infection in childhood, which leads first to superficial gastritis, and then may evolve to atrophic gastritis, intestinal metaplasia, dysplasia and, finally, cancer.
To stop this cascade in its tracks we must eradicate H. pylori sufficiently early, i.e. before the development of so-called ‘gastric pre-cancerous lesions’ such as atrophic gastritis and so on.
This is what we currently do in Europe when we encounter someone with H. pylori, and, thanks to prospective and interventional studies in Asia, we now have several data showing that this works. Indeed, in Asia, a lot of massive eradication programmes have been implemented that it would not be possible to introduce in Europe, because the overall incidence is not very high. And, of course, massive eradication with the use of several antibiotics is not without secondary effects on the microbiota or possible implications for antimicrobial resistance, which is a huge challenge.
It would not be cost-effective to attempt massive eradication in Europe, but it could be proposed in high-risk populations – for instance, people whose family members have gastric cancer or patients with a history of atrophic gastritis, and so on. People in some European countries, including Portugal and Eastern European countries like Russia, are also at a higher risk, which may indicate ethnic factors that should be taken into account. There are also data to suggest that people who use proton pump inhibitors long term may be at risk of gastric cancer, so these people could also be targeted by a massive eradication programme, but more research is needed to support that.
Besides the eradication of H. pylori, another important factor in prevention is maintaining a healthy lifestyle by avoiding salty and smoked foods, eating food rich in fruit and vegetables, and staying physically active. More and more research is coming forward to show that this is important in order to reduce your risk of all cancers, including gastric cancer.
In the future, it may be that gastric cancer treatment can be implemented using a vaccine against H. pylori, which would avoid the challenges of side effects and antimicrobial resistance that come with massive eradication. A lot of work is being done on a vaccine and clinical trials have been started, but unfortunately the data are not yet perfect.
How would you evaluate the level of research being done on gastric cancer?
In Asia, where the incidence is very high, there is a lot more research going on than there is in Europe, where the topic of gastric cancer is somewhat neglected and gastric cancer treatment needs further research. This is due in part to a lack of funding. In France, for example, there are around 43,000 new cases of colon cancer every year compared to just 6,000 new cases of gastric cancer. Health authorities, foundations and other research-funding bodies are interested in numbers, so they are not convinced to invest heavily in gastric cancer treatment and studies. As a result, there are few research groups working on gastric cancer, as compared for instance to colon cancer, in Europe. Indeed, much more fundamental and translational research is necessary to better understand the gastric carcinogenesis and eventually to identify the new therapeutic agents.
More research is also needed in the field of clinical research in gastric cancer. Indeed, very little progress has been made in terms of cure of advanced gastric cancer, especially when compared to colon cancer, during the last decades. Especially, the recent emergence of new treatments, like immunotherapies, holds promise for the future, but much more work has to be done to confirm their efficacy in advance gastric cancer treatment.
Gastric cancer rates are largely decreasing; what is behind this trend?
Historically, we can distinguish between two types of gastric cancer: distal and proximal, or cardia, cancer. Infection with H. pylori is related mainly to distal gastric cancer, while proximal gastric cancer is most likely related to reflux.
We used to believe that distal gastric cancer would disappear with the disappearance of H. pylori – and nowadays, thanks in part to better hygiene, the rate of infection with H. pylori is decreasing all the time and so is the development of gastric cancer.
However, a new phenomenon has been recently observed in the USA with a dramatic increase of gastric cancer incidence in women between 40 and 50. This in itself is unusual, because gastric cancer is typically a disease of the elderly. This cancer does not seem to be related to H. pylori but most likely to autoimmune gastritis, which is in keeping with a rise in autoimmune diseases in general, and particularly in women. In the future, this new ‘third type of gastric cancer’, which is concentrated mainly in the corpus, may well become a significant problem, and there are now ongoing studies in Europe to look into this trend.
To come back to your question, then, the problem of gastric cancer may not actually be disappearing at all.
This article will appear in issue 7 of Health Europa Quarterly, which will be published in November 2018.