Cancer is usually considered a disease of older people. But even among young adults under the age of 50, the number of cancer diagnoses and deaths has increased significantly since 1990. This is the result of a study based on data from 204 countries. According to this, breast cancer causes the most cancer-related deaths in adults under 50 years of age worldwide. Researchers are reporting the greatest increase in cases for trachea and prostate cancer. Lifestyle factors such as diet, tobacco and alcohol use, and lack of physical activity are likely to play a role.
Cancer is one of the most common causes of death worldwide. Since one of the most important and unavoidable risk factors is age, older people are predominantly affected. However, several studies from different regions of the world have also found an increase in cancer among adults under the age of 50. However, these studies only related to individual countries or certain types of cancer, so that a comprehensive picture has not yet emerged.
Cancer cases are increasing
A team led by Jianhui Zhao from Zhejiang University in China has now, for the first time, globally evaluated how the frequency of 29 different types of cancer has changed in adults between the ages of 14 and 49 since 1990. As a basis, the researchers used the Global Burden of Disease data set from 2019, which records the number of cases and deaths of numerous diseases, including cancer, for 204 countries worldwide. The result: “In 2019, 3.26 million new cases of cancer were diagnosed worldwide in under-50s,” reports the team. “That’s 79.1 percent more than in 1990.”
Although proportionately more people survived their cancer, the number of cancer-related deaths also increased due to the higher number of cases, from 0.83 million in 1990 to 1.06 million in 2019. According to the data, the most common causes of death were cancers of the digestive system, including colon cancer , gastric cancer and pancreatic cancer, cancers of the respiratory tract such as lung cancer and tracheal cancer, and breast cancer. The researchers recorded the most significant increase in new cases of trachea and prostate cancer. In contrast, the incidence of liver cancer in younger people decreased.
Country and gender differences
Looking at the global distribution, Zhao and his team found that new cancer cases among the under-50s increased most in North America, Australasia, and western Europe. However, the highest death rates were recorded in Oceania, Eastern Europe and Central Asia. Women were more affected than men in terms of both caseload and mortality, particularly in low- and middle-income countries. One reason for this gender difference is the high proportion of breast cancer cases, which almost exclusively occur in women.
In search of the causes of the increase in early cancer cases, the researchers analyzed the influence of various risk factors. “Changes in diet, lifestyle and environment since the turn of the 20th century may have affected the incidence of early-stage cancer,” they write. They identify the consumption of tobacco and alcohol, a diet with a lot of red meat, a lot of salt and little fruit and vegetables, lack of exercise, obesity, high blood sugar levels and environmental toxins, which enter the body through the air we breathe, as important risk factors.
Early detection and prevention
“Promoting a healthy lifestyle, including a healthy diet, limiting tobacco and alcohol consumption, and appropriate outdoor exercise, could reduce the burden of early cancer,” the research team writes. “It is also worth investigating whether early detection and prevention programs for cancer should be expanded to include people aged 40 and over.” However, further studies are required to assess the benefits of such a measure.
In a commentary accompanying the study, also published in the journal BMJ Oncology, Ashleigh Hamilton and Helen Coleman from Queen’s University, Belfast, write that the results challenge previous perceptions that cancer is extremely unlikely in younger age groups . “It is important to educate both the public and health care professionals about the possibility of certain cancers in younger adults to enable earlier diagnosis, which in turn improves treatment outcomes,” they write. “Measures for prevention and early detection are urgently needed, as is the identification of optimal treatment strategies for early-onset cancers. A holistic approach should be chosen that takes into account the special needs of younger patients when providing supportive care.”
Source: Jianhui Zhao (Zhejiang University School of Medicine, China) et al., BMJ Oncology, doi: 10.1136/bmjonc-2023-000049