The number of people under the age of 50 who develop cancer has increased by almost 80 percent worldwide in the last thirty years. Cancer mortality in this younger age group has also increased by almost 28 percent since 1990. More than one million people under the age of 50 now die of cancer each year. This number will increase by another 21 percent by 2030, the number of younger cancer patients will then have increased by 31 percent, researchers calculate in a study which appeared this week in BMJ Oncology.
Cancer is by far most common in people over the age of 50, but previous studies in various countries have suggested that the disease is also becoming more common in younger people. The new study charts for the first time globally how many adults under the age of 50 developed and died from cancer in recent decades. The researchers looked at 29 types of cancer and used data from 204 countries. They found large differences between countries and between different cancer types.
The number of people under the age of 50 who develop cancer rose from 1.82 million in 1990 to 3.26 million in 2019. The sharpest increase in the number of cancer patients in that period was in the United Arab Emirates, Qatar and Saudi Arabia. The highest rates of cancer diagnosis were in high- and middle-income countries and among people aged 40 to 49. Breast cancer claimed the most victims in 2019, followed by cancer of the respiratory tract, stomach and intestines.
Genetic factors
Per capita, North America, Oceania and Western Europe had the highest rates of cancer under the age of 50. The risk of dying from cancer for people under the age of 50 was lower in the richer countries than in the poorer ones. The researchers saw the highest mortality in Eastern Europe, Central Asia and the Oceania region.
Scientists do not yet fully understand how this sharp increase in cancer among younger adults can be explained. Genetic factors may play a role, as well as environmental pollution, for example. But poor lifestyle habits, such as smoking, drinking alcohol, little exercise and an unhealthy diet, are the main risk factors, the researchers write.
That is very likely, says Otto Visser, head of the Dutch Cancer Registry. “Worldwide you see that cancers related to Western lifestyles are rising in particular. For example, breast cancer was hardly seen in developing countries fifty years ago. But the number of children that women have there is decreasing, mothers are breastfeeding less and the diet and lifestyle in those countries are changing.” As a result, breast cancer has increased sharply in all those countries, says Visser, as have cancers related to obesity, such as colon and kidney cancer, and lung cancer, due to smoking. Visser: “You see the same patterns everywhere. And often younger people are the first to switch to an unhealthy, Western lifestyle.”
Better detection
Part of the measured increase in absolute numbers of cancer diagnoses can be explained by population growth in recent decades. The size of the world’s population increased by 54 percent between 1990 and 2019, from 5 billion to 7.7 billion. In addition, the detection of all kinds of cancer is also improving, so that also plays a role in the increase in the number of cancer patients. But on top of that comes the increase due to the changed lifestyle. “In the Netherlands, too, the number of women with breast cancer per 100,000 inhabitants has risen in the past thirty years. That is independent of population growth,” says Visser.
The sharp increase in the number of patients and the alarming prognosis for 2030 means that the demand for medical care will only increase. This poses a major challenge for lower-income countries. “Developing countries also have a lot to do with infectious diseases. On top of that are now the diseases that are caused by the Western lifestyle, ”says Visser.
This study underlines that countries should invest more in prevention, such as curbing tobacco and alcohol consumption and promoting a healthy lifestyle, Visser believes. “Developing countries should also start doing this now. But that’s easier said than done. That is not easy here either.”
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