Prevention – “Colonoscopy is the most important preventive method”

Mr. Truninger, why is colon cancer still one of the most common types of cancer?

The number of cases varies widely around the world, likely due to lifestyle and diet. However, the trend shows that new cases tend to increase in developing countries, while they decrease in the United States and other industrialized countries.

Isn’t this good news for us?

However, a distinction must be made: the positive development only concerns people over 50 years of age. The trend is reversed among the youngest, which means that there is a significant increase in new cases.

What are the reasons?

Lifestyle factors in particular play a role here, including lack of physical activity and a diet that is too high in fats and sugars and the associated obesity. For this reason, some professional societies now recommend starting colorectal cancer screening as early as age 45. The famous American association of gastroenterology AGA, for example, currently advertises with the slogan “45 is the new 50”

Are there new options – colonoscopy not really popular?

Regarding the development of colorectal cancer, there is indeed a lot of new knowledge about the early molecular changes of this disease. However, this knowledge is not yet reflected in the widespread use of new preventive tests: colonoscopy and regular examinations of invisible, so-called occult, blood in the stool remain the most important methods.

What are the typical signs of colon cancer?

Unfortunately, there are no reliable early symptoms. Colorectal cancer and its precursors, called polyps, grow slowly over years. Possible warning signs are blood in the stool, changed bowel habits, flatulence with involuntary stools or mucus, abdominal cramps, fatigue, weight loss. But as I said, people with polyps and curable colon cancer in the early stages usually feel little or nothing. This is why prevention is so crucial. In Switzerland, the health insurance companies cover the costs of a colonoscopy for 50 to 69 year olds.

Do men seem more prone to colon cancer than women?

In fact, many studies show that men are more likely to develop colon cancer. The same goes for polyps. However, the causes of this difference are still largely unknown. According to a new German study, well-known risk factors such as diet, obesity, smoking, physical exercise, etc. can only explain about half of the increased risk in men. The causes of the second half of the sex-specific difference are therefore unclear; hormones may play a role here.

Female hormones would have a certain protective effect: how to explain this?

The development and progression of colorectal cancer appears to be hormone-dependent. When estrogens, i.e. female hormones, bind to receptors, they can influence many molecular signaling pathways and therefore cell function and behavior. Overall, however, the cellular and molecular mechanisms of estrogen-related protective effect are still poorly understood. It should be noted that not only are women less likely to develop polyps and colon cancer, but they also develop them an average of four to eight years later than men. It can also be due to the influence of hormones.

This is also supported by the fact that women who have undergone hormone replacement therapy have a lower risk of colon cancer.

Indeed, various studies have shown that hormone replacement therapy at menopause reduces the risk of colorectal cancer. However, the data is sometimes controversial. Because in some meta-analyses – by which is meant the evaluation of the results of many studies on a subject – the protective effect of hormone replacement therapy has been evaluated as neutral or at the lowest. Taking hormones only to prevent colon cancer is therefore not recommended – also because of possible side effects.

What other factors play a role in the development of colorectal cancer?

Polyps and colon cancer largely share the same risk factors. Their frequency increases with age, and the risk can be influenced by lifestyle and diet: smoking, lack of exercise, obesity, increased alcohol consumption and a diet high in fat with a lot of red meat increase the risk. On the other hand, a healthy lifestyle with a normal weight, lots of exercise and an abundant supply of fiber, vegetables and fruits can reduce it. Patients with inflammatory bowel disease and type 2 diabetes generally have an increased risk of bowel cancer. There are also people with a family history of colon cancer. For these risk groups, the age for preventive colonoscopy must be determined individually.

If someone nevertheless falls ill with colon cancer: What are the chances of recovery today?

Fortunately, the chances of survival here and in other industrialized countries have increased in recent years. This is mainly due to improved treatment options. Today, tumor tissue is routinely examined for various genetic mutations that are decisive for the composition of chemotherapy. The treatment of colorectal cancer is becoming increasingly personalized, ie adapted to the patient.

Are there gender differences here too?

Yes, women have a slightly better chance of surviving – especially if the disease occurs at a younger age. This benefit can also be hormonal.