The Global Rise in Early-Onset Cancers: Time to Rethink Etiologies, Surveillance, and Action

The increasing incidence of early-onset cancers, defined as those diagnosed in individuals aged 50 years or younger, has been observed in different regions of the world over recent decades. Epidemiological studies indicate a consistent rise in these cases across several tumor types, including colorectal, breast, pancreatic, stomach, and liver cancers. Although advances in screening and diagnostic programs may explain part of this increase, the magnitude and distribution of the phenomenon suggest the influence of broader structural factors. High-penetrance genetic mutations, such as those associated with the BRCA1/2, TP53, and MLH1 genes, are recognized in hereditary cancer syndromes related to early-onset disease; however, they occur at low frequency in the general population and do not, by themselves, explain the observed population-level increase. In this context, the literature highlights the likely contribution of environmental, behavioral, and social factors, including lifestyle changes and cumulative exposures throughout the life course, often beginning during the intrauterine period or early childhood. Among these factors are increased consumption of ultra-processed foods, reduced physical activity, circadian rhythm disruptions, alcohol consumption, chronic infections, and exposure to environmental pollution. The interaction among these determinants reinforces the importance of integrated strategies for surveillance, prevention, and health promotion. Although much of the available evidence originates from high-income countries, recent studies indicate similar trends in middle- and low-income countries, including Brazil, suggesting that the global burden of early-onset cancers may become even more significant in these contexts. In light of this scenario, there is a need to strengthen longitudinal research, incorporate emerging technologies such as artificial intelligence and digital tools applied to health surveillance, and expand public policies focused on prevention, screening, and health education through collaboration among researchers, health professionals, and policymakers.