Uptick in cancer cases among younger generations perplexes scientists

The news that the Princess of Wales has cancer has drawn more attention to the rising incidence of this disease among young adults, challenging the traditional association of cancer with aging. Age is a key risk factor for cancerous tumor development, as failing bodily control systems allow cells to grow unchecked: the older you are, the greater the risk. However, in recent years, the scientific community has identified a new phenomenon in the spread of the disease: “There are documented trends showing a subtle rise among young people. The exact cause remains unknown, but some speculate that environmental factors, nutrition and exposure to unidentified substances in the womb might be the reason,” said Martín Lázaro, an oncologist at Vigo University Hospital (Spain) and president of the Oncological Society of Galicia. A study published in BMJ Oncology estimates that the global incidence of early-onset cancer (people under 50) has increased by 79% in three decades. According to the study, “Dietary risk factors (diet high in red meat, low in fruits, high in sodium and low in milk, etc.), alcohol consumption and tobacco use are the main risk factors underlying early-onset cancers.”

Cancer is the leading global cause of death. In 2020, around 10 million people lost their lives to this disease, according to the World Health Organization. The scientific community is studying the changing trends in cancer incidence, particularly the rise among younger individuals. Experts caution that current evidence on the causes is still limited and evolving. Mariano Provencio, an oncologist at Madrid’s Puerta del Hierro Hospital, recommends a cautious approach to all the theories. “There is a rise in cancer cases among younger people, but each one should be evaluated individually. While some lifestyle habits are linked to cancer, there are many instances of lung tumors in young non-smokers. This is concerning as genetic factors may play a role, yet current detection methods are unable to identify them.”

Experts are working to understand the reasons for this trend. Different types of cancers are being studied, such as breast and colon tumors, with a focus on the increasing prevalence of gastrointestinal tumors. A U.S. study published last year in JAMA Network Open revealed that from 2010 to 2019, gastrointestinal cancers (colon, pancreas and stomach) had the fastest-growing incidence rates among all early-onset cancers, while breast cancer was the most prevalent. Cancers of the urinary system and the female reproductive system followed in terms of fast-growing incidence rates. Another study published in Science also found that early-onset colorectal cancer is increasing globally and is expected to become the leading cause of cancer death in people aged 20 to 49 in the United States by 2030. However, the exact reasons and pathophysiology remain unknown.

Research published in Cancer Discovery last year highlights the increasing incidence of early-onset gastrointestinal cancer, possibly linked to non-hereditary factors like behavior, lifestyle, diet and environment. “The relatively low proportion of hereditary cases among the early-onset gastrointestinal cancer population indicates a potential key role for environmental and behavioral factors in pathogenesis. Genetic de novo alterations, environmental factors, lifestyle changes including obesity, diet high in red or processed meat, and lack of physical activity are possible causes of the shift in burden of disease in the younger population.” In other words, everything may have had an impact, starting from a very young age.

Other factors contributing to the increase in cancer in younger people are better diagnosis and early detection methods. Nonetheless, Lázaro has reservations about this theory. “There is debate about the influence of diagnostic improvements, because cancer will be detected eventually — if not at age 42, then at 43.” The oncologist says cancer might go undetected in young people because it presents non-specific symptoms earlier in life. “This delay in diagnosis is why some young people already have advanced cases, possibly resulting in a poorer prognosis.”

The Princess of Wales has not revealed her type of cancer or prognosis. The only detail she provided was that she was receiving “preventive chemotherapy,” a treatment typically used to stop cancer from returning. “Preventive chemotherapy (also called adjuvant therapy) is often used after primary therapy, such as surgery, to reduce the chances of the cancer coming back and spreading. Undetected, microscopic cancer cells may still be present after successful removal of the visible tumors. Chemotherapy type and duration are based on cancer type and stage, determined by examining removed tissue,” said Lawrence Young, a professor of molecular oncology at the University of Warwick (U.K.), in a Science Media Centre article.

Psychological impact

Early-onset cancer has a significant psychological impact on patients. Tania Estapé, president of the Spanish Society of Psycho-Oncology (SEPO), notes that a cancer diagnosis is always shocking, but even more so for young adults. “It is very disruptive for the lives of adults of working age who may have young children. This leads to increased hostility, anxiety, and a sense of injustice. Studies indicate that women with young children always prioritize their children above themselves,” said Estapé. In her announcement, Catherine clarified that she and her husband decided not to make any public statements while they figured out the best way to explain the situation to their three young children.

Paco Gil, head of psycho-oncology at the Catalan Institute of Oncology, noted that the princess’ situation is unusual in every sense. “For her, there’s just no comparison in real life. Most people can keep this type of news within the family. But when a famous person like the Princess of Wales goes through something like this and openly talks about it, it helps make it more normal.” It also raises awareness and dispels stigmas.

Experts say how a cancer patient copes with the disease depends on many factors, such as age. Older people tend to exhibit more “serenity,” says Estapé. The cancer prognosis and individual circumstances also play crucial roles. Gil agrees that the psychological impact of a cancer diagnosis is typically higher for younger people. “Getting diagnosed with cancer feels like a real shake-up of everything you thought you knew. And when you’re under 50, it’s even more unexpected. There’s this fear that all your dreams in life will be dashed.”

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