Why Are More Cancers Being Diagnosed at a Young Age?

BARCELONA, Spain — Over three decades, from 1990 to 2019, the global incidence of early-onset cancer (EOC) increased by 79.1%. Irit Ben-Aharon, MD, PhD, from the Rambam Health Care Campus in Haifa, Israel, presented this alarming figure during her keynote lecture at the European Society for Medical Oncology (ESMO) Annual Meeting 2024. The session featured Shuji Ogino, MD, PhD, from Harvard Medical School and Brigham and Women’s Hospital in Boston.

The available data suggested that we are facing a true epidemic that the international oncology community can no longer ignore.

Generations at Risk

Ogino emphasized that the incidence of EOCs, defined as cancers diagnosed in individuals younger than 50 years, has been increasing sharply for decades. This rise is just the tip of the iceberg, as once these younger patients age, it will also lead to an increase in chronic diseases and cancers in older adults. Notably, many of these cancers affect the gastrointestinal tract and are linked to obesity, highlighting the importance of the microbiome and diet.

“Focusing solely on the present is not enough to fully understand the reasons behind the increase in cancers among the younger population,” Ogino said, citing a recent editorial he co-authored, which stressed the importance of assessing exposure to risk factors at a young age and continuing periodic checks, even in individuals without cancer.

Epidemiologic data show, for example, that the incidence of colorectal cancer across all ages has been rising since the 1950s, while early-onset colorectal cancers began to increase only in the 1990s. How can this 40-year gap be explained? The postwar period may represent a turning point: During those years, there was a change in lifestyle and numerous environmental factors, so much so that the numbers show an effect of the birth cohort. In other words, children born from the mid-20th century onward were exposed from childhood to known risk factors such as an unhealthy diet, excess weight, and sedentariness.

“In recent years, there have been various reports in the international literature of an increase in cancers among the young. Some of these publications have also been seen significant media attention,” explained Massimo Di Maio, MD, PhD, president-elect of the Italian Association of Medical Oncology, speaking with Univadis Italy, a Medscape Network platform. Di Maio said these publications confirm the perception, often reported by oncologists, that there has been an increase in cases among the young in recent years and for various cancers. He stressed that EOCs can only be understood by looking at the past of these generations and keeping an eye on their future health.

“Attention to risk factors and lifestyle matters a lot from childhood. It is realistic to think that if the body’s cells undergo more damage, a cancer can develop earlier at the same chronological age,” explained Di Maio.

Changing the Perspective

Ogino emphasized that studies should be designed to collect data and samples from the early stages of a person’s life and preserve this information over time.

This is easier said than done. “Collaboration between researchers focusing on adult subjects and those dedicated to pediatric research is not particularly active. Moreover, it is difficult to find financial support to carry forward such studies, and researchers may be reluctant to see the results of their research decades after starting it,” Ogino explained.

One possible approach is to use already available data from pediatric cohorts. These data, which often include biological samples and genetic information, have been collected in populations of children who have now become adults and can consequently help understand exposures to risk factors during childhood and then link them with outcomes in adulthood. A prime example is the British birth cohort studies: The first, known as the National Survey of Health and Development, began in 1946.

“Pediatric databases are not currently used to study diseases in the adulthood of the subjects recruited,” Ogino said, explaining that this results in a loss of valuable data. Returning to the question of whether these cancers are linked to the environment or genetics, he emphasized that genes also play a role, and it is important to link these two aspects for more targeted prevention.

To curb this epidemic in the era of oncologic screenings and anti-obesity drugs, Ogino suggested rethinking prevention strategies, such as starting screening earlier or considering pharmacologic prevention.

However, Di Maio believes this approach is premature. “Screening programs are based on demonstrations of efficacy that require years to establish. In my opinion, it is not reasonable at this time to think about changes to screening pathways that involve lowering the start age because such a change would not be sufficiently supported by evidence of benefit,” he said. Di Maio also thinks it is premature to commit to the use of anti-obesity drugs for prevention, beyond the indications for which they have been approved so far. “The fight against overweight and obesity is not just pharmacological,” he said, emphasizing the importance of lifestyle.

Ben-Aharon declared financial interests with AstraZeneca, MSD and Merck (invited speaker), and Bristol Myers Squibb and Astellas (advisory board member). Ogino and Di Maio, who was not involved in the session, declared no conflicts of interest.

Cristina Ferrario is a molecular biologist and former researcher in molecular oncology at three institutes in Milan. She has a master’s degree in communication and health from the University of Milan, Milan, and a master’s degree in cancer genetics from the University of Pavia, Pavia, Italy. She has worked as a science journalist for more than 20 years.

This story was translated from Univadis Italy using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.