In the middle of the month, the annual congress of the European Society for Medical Oncology (ESMO) was held in Paris, where the latest advances in cancer were presented. One of the most noteworthy attendees was Josep Tabernero (Barcelona, 1963), who chaired ESMO from 2018 to 2019.
Tabernero, in addition to being one of the most relevant oncologists at European level, is head of the Medical Oncology Department at Vall d’Hebron Hospital (Barcelona), director of the Vall d’Hebron Institute of Oncology (VHIO) and founder and medical director of the Institute of Oncology of Barcelona (IOB). Expert in colorectal cancer, talks to EL PERIÓDICO about the tumor. the most common tumor in Europe.
You say that, no matter how well it is done, colon cancer is associated with aging.
Solid tumors, unlike hematologic tumors, arise from multiple genetic alterations. So, those tumors that appear due to multiple genetic alterations need time for all those alterations to occur, because they do not occur all at once. And this is what happens with colon cancer. The colon is a viscera that suffers a lot of continuous wear and tear because all the feces pass through it, everything we eat, the good and the bad.
And this causes cancer?
At the same time, the colon also regenerates a lot. The organism itself is repairing the cells that have alterations. But sometimes these mechanisms [de corrección] fail. And, of course, the more time passes, the older the person is, the more chances there are that some repair mechanism does not work properly and genetic alterations accumulate, which in the end lead to polyps.
Does a polyp already indicate some genetic alteration?
Yes. When there is a polyp, there is already some genetic alteration that causes the cells to overgrow. Polyps, normally, until they become malignant, are cells that we consider benign, but they overgrow. But, if they accumulate more genetic errors, a tumor can form. That is why it is a disease that is mainly linked to age.
What is the average age of onset?
67 years. It is true that there is a percentage of colon cancer patients who have some hereditary alteration, that is, some gene that they inherited that is altered, and that puts them a little bit more at the front of the race. That is why we are seeing more and more colon cancer tumors being diagnosed in younger people, under the age of 50. If caught early – in stages one or two – colon cancer has a 90% survival. In stage three, between 60% and 70%. And when it metastasizes, survival does not reach 20% in five years.
“We are seeing more and more colon cancer tumors being diagnosed in younger people, under the age of 50.”
What risk factors play a role in this tumor?
For example, diet. African countries have a lower incidence of colon cancer because they generally eat more fiber than we do. We are in an intermediate position between the Nordic countries and the United States – where the incidence of colon cancer is very high – and the African countries – where it is lower. The Mediterranean diet protects us in this sense but, if we lose it, we will have more colon cancer.
What is the incidence?
In Europe it is the most frequent tumor, affecting both men and women. In women, breast cancer is more frequent. In men, prostate cancer and lung cancer. But, if we consider both men and women, the most frequent is colon cancer.
Can irritable colon lead to cancer?
Irritable bowel disease certainly does not. Inflammatory bowel diseases can, such as ulcerative colitis and Crohn’s disease. Why? Because they are diseases that produce chronic inflammation and this has a higher risk of producing cancer. The diet that favors colon cancer is low in fiber and high in fat. That is why we should only eat red meat once or twice a week, because red meat – a sirloin steak, for example – unlike white meat, has fat within the fiber. In white meat, which is mostly poultry, the fat is always outside the fiber. In contrast, in red meat, the fat is inside the fiber. So, even if you take the fat out, there is still fat inside the fiber.
“Irritable bowel does not lead to cancer. Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s, can.”
With what are the main advances in colon cancer?
Many. It is one of the tumors whose genetic alterations are best known. Why? First, because there are animal models. Second, because we can do colonoscopies. We know that the polyp is a premalignant entity, which can degenerate, and colonoscopies help us to detect these polyps. In other cancers, such as breast cancer, for example, we cannot detect premalignant entities. What breast cancer has gained a lot is early diagnosis thanks to mammograms and MRIs.
And for colon cancer there is the fecal occult blood test.
Yes, with this we do prevention and early diagnosis. It is offered to the population between 50 and 70 years of age, which is the age range in which we most frequently diagnose colon cancer. These are the so-called screenings. Now it is being discussed whether we should lower the age to 45 or 40, and it will end up being done, first at 45 and then at 40.
What happens when the stool blood test is positive?
The patient undergoes a colonoscopy, which allows us to diagnose smaller tumors or even polyps. We are performing less and less aggressive surgical techniques. And, in addition, there have been many advances in the subclassification of the disease. Fifteen years ago we spoke of one colon cancer; today, we speak of up to 10 different subtypes. And there are increasingly more personalized treatments, targeted therapies, based on the genetic alterations of each tumor.
“We are performing less and less aggressive surgical techniques. And, in addition, there have been many advances in the subclassification of the disease.”
How did the pandemic affect the detection of this tumor?
Colon cancer screening was halted from March to June or July 2020. That led to almost 12% fewer tumors being diagnosed overall, but this is now recovered. But in addition to these screenings, which diagnose silent tumors, it is very important that the population continues to keep in mind that when faced with a 15-day loss of blood, weight loss without an affiliated cause or fatigue, they should consult a doctor. The population should not lower their guard because what we saw between 2020 and 2021 is that tumors were diagnosed more advanced because people consulted less, as access to the system was less and there was fear.