Why is cancer younger? Research analysis

Statistics from around the world show that among adults under the age of 50 morbidity is increasing for more than a dozen types of cancer. By forecasts scientists, between 2019 and 2030, the number of early cancer cases will increase by approximately 30%.

Possible reasons for this trend and future cancer research analyzed Nature edition.

In the US, colorectal cancer, which usually affects men over 60, became the most common a type of oncology from which men die before the age of 50. Among young women, he is in second place.

The exact reasons for the increase in the number of cancers are unknown. Rising obesity rates and early cancer screening are some explanations, but they cannot fully explain the increase.

“If this were the only indisputable evidence, our studies would at least point to one factor. But it doesn’t appear to be the case – it’s probably a combination of many different factors.” – says Sonya Kupfer, a gastroenterologist from the University of Chicago.

Scientists believe that the answer lies in studies that tracked the life and health of children born half a century ago.

The incidence of cancer is increasing worldwide

In some countries, in particular in the USA, mortality from cancer decreases through increased screening, reduced smoking rates and new treatments. However, the incidence of cancer is increasing globally.

Cancer in adults under the age of 50 still accounts for only a small proportion of the total number of cases, but it is becoming more common.

Combined with the increase in the global population, the number of deaths from early cancer increased by almost 28% between 1990 and 2019.

Most often, such cancer affects the digestive system, in particular colon, pancreas and stomach. But the number of diseases and other types of cancer – breast and prostate – is increasing.

Genetic clues to the causes of cancer

The rise in gastrointestinal cancers in many countries coincides with the prevalence of obesity and the trend towards eating processed foods. However, this is not the only reason.

The US National Cancer Institute and Cancer Research UK support programs to find other factors that contribute to the development of cancer in young people. One approach is to look for genetic clues in “early” tumors that can distinguish them from tumors of the elderly.

Pathologist Shuji Ogino from Harvard Medical School in Boston and colleagues identified some possible characteristics of “early” aggressive tumors. For example, they sometimes oppress the body’s immune response to cancer. However, the researchers did not find a clear distinction.

Scientists also studied microorganisms that live in the human body. Disturbances in the microbiome, such as those caused by dietary changes or taking antibiotics, have been linked to inflammation and an increased risk of certain diseases, including some forms of cancer.

Increasing the scope of research may help find the true cause. Vanderbilt University Medical Center oncologist Kathy Eng is developing a project to study the relationship between the composition of the microbiome and the onset of cancer at a young age. She plans to combine her data with that of colleagues from Africa, Europe and South America.

Tomotoka Ugai, a cancer epidemiologist at Harvard Medical School, instead plans to study differences between countries. For example, Japan and South Korea are located next to each other and are similar economically. However, the rate of colorectal cancer among young people in South Korea is increasing faster than in Japan.

According to Barbara Cohn of the Auckland Institute of Public Health, researchers will also have to look back to understand the reasons for the increase in cancer at a young age. After all, it can occur many years after exposure to carcinogens, such as asbestos or cigarette smoke.

For this, scientists will need data collected from thousands of people over 40-60 years. Kohn already has data and blood samples from about 20,000 pregnant women collected since 1959. The researchers observed many of the first participants and their children.

According to the previous ones by the resultsthere is a possible link between early colorectal cancer and prenatal exposure to a certain synthetic form of progesterone, which is sometimes taken to prevent premature birth.

Scientists also plan to study the impact of prenatal stress, including alcohol, tobacco smoke and malnutrition, on the risk of developing cancer at a young age.

We will remind, according to researchover the past 30 years, the number of new cancer cases under the age of 50 worldwide has increased by 79%.