Several observations suggest that this increase in incidence is caused by a decrease in the effectiveness of our anti-cancer defenses during aging.
The onset of cancer is not an instantaneous phenomenon, which occurs overnight. On the contrary, it is for years and decades that body cells have accumulated multiple genetic mutations that have transformed their functions and allowed them to grow and invade the body.
The sharp increase in cancers at advanced ages is therefore partly a reflection of the time required by cells to accumulate this “arsenal” of mutations.
However, several observations suggest that these mutations are not the only reason why the elderly are at greater risk of cancer. For example, a very large number of mutations appear during the development of the body, so that when our growth ends, at the end of adolescence, we have already accumulated the majority of these precancerous mutations.
In this sense, studies indicate that 33% of women in their forties already have small breast tumors and nearly 40% of men of the same age have them in the prostate. Yet a much smaller percentage of the population (between 10% and 15%) will develop either of these cancers, even at advanced ages.
In other words, the increase in cancer with age cannot be explained solely as an accumulation of mutations by cells during aging.
Our lifestyle habits promote or prevent the appearance of cancer
The environment in which the abnormal cells that seek to become cancerous are found is normally very resistant to the growth of these tumors. It is an absolutely essential adaptation to the evolution of complex organisms like that of the human being.
Indeed, the process of cell division necessary to maintain the functioning of our body generates billions of cells per day, including one million abnormal cells, and it is therefore essential to prevent these cells from reaching a cancerous stage.
Our lifestyle habits, however, can significantly alter this environment and make it more permissive to the growth of abnormal cells. Smoking, poor diet, excess weight or physical inactivity all have the common characteristic of promoting inflammation of this environment, a condition that promotes the acquisition of cancerous properties by abnormal cells.
As we age, the impact of these bad habits becomes more and more important and the weakening of our normal defense mechanisms therefore increases the likelihood that an abnormal cell will escape these defenses and develop into mature cancer. .
Help your immune defenses
Although more common at older ages, cancer is not an inevitable consequence of aging. But to prevent this disease, it is absolutely necessary to preserve our natural defenses as much as possible, in particular by limiting the development of chronic inflammation to a minimum.
A diet richer in plants and devoid of bad foods overloaded with harmful sugars and fats, regular physical activity and maintaining a normal weight remain the best strategy for living a long time without being affected by cancer.
Degregori J. Challenging the axiom: does the occurrence of oncogenic mutations truly limit cancer development with age? Oncogene