06 Feb

Dr Castells: “We need to anticipate the appearance of colorectal cancer”

Dr Castells: “We need to anticipate the appearance of colorectal cancer”

Doctor Antoni Castells, specialist in gastroenterology, is medical director of Barcelona’s Hospital Clínic, co-coordinator of the Barcelona’s colorectal cancer detection programme and medical adviser to the biotechnology company GoodGut. In the research field, Castells leads the Gastrointestinal and Pancreatic Oncological Research Group of the August Pi i Sunyer Biomedical Research Institute (IDIBAPS) and of the Liver and Digestive Diseases Biomedical Research Centre (CIBERehd). We are interviewing him because GoodGut has just presented the first positive results from the clinical trial conducted of the new non-invasive RAID-CRC test for preventing and diagnosing colon and rectal cancer, which could be on the market in 2019.

What are the most pressing challenges in combating colorectal cancer?

In my opinion we are currently facing three main generic challenges in the research against colon and rectal cancers. The first is to try to make treatments more effective and less toxic, an area in which significant progress has been made in recent years and where the prognosis has improved. The second is to seek less invasive diagnostic methods. Currently the main method is via colonoscopy, an excellent and very effective test, but one which is invasive and requires preparation meaning that, although rare, the procedure may lead to complications. The third is to anticipate the appearance of cancer and implement strategies helping us to prevent it. We need to detect it at an earlier phase, when it is what we call a polyp or adenoma, to prevent the lesion progressing to become cancer.

Are these challenges faced worldwide?

Yes, in most developed countries we are more or less at this same preventive or prevention research stage.

Is the primary state of the polyp not currently diagnosed?

Yes, we have various ways of detecting it in this phase. The most effective is the colonoscopy. As I was saying before, this is a tool that is used a lot because very small lesions, such as polyps, can be detected. Then there are other methods to identify persons with a high probability of having this lesion, to find out whether it is worth carrying out a colonoscopy. Of these methods, which we call markers, the most normal is detecting blood in stools. Finding blood in stools can mean many other things, not necessarily either a polyp or cancer, but we feel that if found it is worth carrying out a colonoscopy on this person. The research by companies such as GoodGut is offering us other markers, at different phases of development and market readiness, which have the same purpose but are not invasive and are more efficient.

What is your assessment of the situation for preventive programmes in Catalonia?

Ten years ago they did not exist, or maybe there were was a pilot study; today the whole population of Catalonia is covered by these programmes which have proven to reduce the mortality rate for colon cancer. As a country we should be pleased we have them. However, for any preventive or therapeutic programme it is also possible to seek even more sensitive and specific strategies that improve mortality and save resources, such as the new test GoodGut is developing.


“The initial results demonstrate that the RAID-CRC is a more specific test than the faecal occult test”

You are a member of the advisory board of GoodGut, the biotechnology company which is developing the RAID-CRC test. How will this test contribute to progress in preventing and diagnosing colon and rectal cancer?

This test is extremely innovative because it is the first time markers deriving from the bacteria present in the gut are used to identify persons with cancer or polyps. We do not really know if the changes in flora precede the cancer or if the cancer changes the flora but, whatever the case, what we see is that these microbial markers identify the persons who have these lesions. The current results, which are still very early, demonstrate this correlation. If these results are confirmed with larger studies, especially in populations without symptoms or any type of manifestation leading them to think they may have cancer, which is the population we consider ideal for screening or prevention, the RAID-CRC could be a more specific test than the current faecal occult blood test. This would reduce unnecessary colonoscopies for those who give a positive result in the blood test and do not actually have cancer, with the benefits this provides for both the person and the health system.

Will the RAID-CRC now be validated in a wider population?

Yes, a validation study will begin shortly on 2,500 people in Germany, a country where colorectal cancer is prevented by means of colonoscopy. This will provide us with colonoscopies from persons with cancer or polyps and those who are healthy. This will allow us to validate the usefulness of the RAID-CRC.

If the results of the final study are positive, will Catalonia again be at the forefront of an advance in biomedical research?

In the field of preventing colon cancer, we are in an excellent position. If the results obtained so far are confirmed with this larger cohort of persons with risk of colon cancer, the country’s position will certainly be consolidated around the world.

According to the World Health Organisation, colorectal cancer is the third most common form of cancer in the world.

That is correct, what happens is that the frequency changes significantly according to country. For example, if we take only Western European countries, the United States and Asia, it is not only the third most common, but becomes the second for women and third for men.

Can you make a future prediction about its incidence?

The tendency we have seen in recent years in most countries without colorectal cancer screening is that the incidence has risen. What we are also starting to see is that in countries that have set up preventive programmes the incidence has stabilised and there are signs that in some it is beginning to fall.

Photo: Hospital Clínic