Early-onset cancer: State of the science and future opportunities

Background: The incidence and mortality of cancers diagnosed before age 50 or early onset cancers (EOCs) have increased substantially worldwide over recent decades. The rising burden of EOCs presents an urgent public health challenge, given their occurrence during key developmental, reproductive, social, and economic life stages.Methods: This narrative review synthesizes contemporary evidence on EOCs across the cancer prevention and control continuum. We summarize current epidemiologic trends, emerging etiologic hypotheses, potential behavioral, environmental, biological, and structural drivers, survivorship needs, financial consequences, palliative and end-of-life care considerations, and future research and policy priorities.Results: EOC trends vary by cancer type, age group, geography, and socioeconomic context, suggesting multifactorial causes. Proposed contributors include obesity and metabolic dysfunction, diet and ultra-processed food, sedentary behavior, alcohol/tobacco use, microbiome disruption, environmental exposures, endocrine-disrupting chemicals, reproductive and early-life exposures, and broader social/structural determinants. Survivors of EOCs face distress, isolation, disrupted relationships and fertility, financial burden, employment and insurance instability, multimorbidity, and palliative and end-of-life care needs.Discussion: The growing burden of EOCs demands coordinated research, clinical, and policy responses prioritizing life-course causal inference, risk prediction and early detection models, mechanistic and translational studies, intervention and implementation science, and survivorship care for individuals living decades beyond diagnosis.