The rising incidence of early-onset cancers has emerged as a sentinel event for epidemiologists and public health officials globally. Traditionally considered diseases of middle and older age, a perplexing and consistent upward trend in cancer diagnoses among individuals under 50 is now capturing global attention and spurring urgent scientific and public discourse. This trend has not only become a recurrent issue of intense media interest, but has also inspired calls for research to explain and respond to this phenomenon.

A critical unresolved question is whether these early-onset cancers represent merely an earlier presentation of traditionally understood malignancies, such as colorectal cancer, or whether they are in fact a distinct category of disease with unique etiological factors and clinical course. Current epidemiological data highlight the inadequacy of established risk factors (including Western dietary patterns, high intake of red and processed meats, alcohol consumption, obesity, physical inactivity, antibiotic use, and microbiome alterations) to fully explain the scale and patterns of increased incidence in younger populations.

Recent thought leaders in the field have posited that while these known factors are sufficient to drive risk in late-onset cases, the dramatic rise in early-onset cancers may signal the emergence of new, potent exposures or combinations thereof, particularly those encountered during critical periods in early life. This shift in perspective challenges researchers to reconcile long-standing multi-factorial paradigms (which emphasize the cumulative and interactive nature of risk factors across transgenerational life courses) with new hypotheses suggesting the possibility of distinct, mono-causal agents or exposures with unique modes of action such as epigenetic modifications.

This Research Topic is dedicated to advancing our understanding of the epidemiological trends and underlying causes of early-onset cancers, with a central focus on life-course exposures (especially physio-chemical, behavioral, and psychosocial) that influence the incidence of and survival from chronic and non-communicable diseases in young populations.

We welcome submissions that address, but are not limited to:

• Analysis of Epidemiological Trends: Examination of incidence patterns and temporal changes in early-onset cancers globally.

• Life-course Physio-chemical, Behavioral, and Psychosocial Exposures: Exploration of how exposure to chemical substances and hormones, dietary habits, lifestyle factors, microbial and antibiotic influences, and psychosocial stressors during distinct developmental windows contribute to the risk and progression of early-onset cancers.

• Novel Etiological Hypotheses: Critical reviews and empirical studies that explore whether early-onset cancers might constitute a new disease entity driven by previously unrecognized exposures or mechanisms, versus the early manifestation of established conditions.

• Mono-causal vs. Multi-factorial Models: Discussions that interrogate the theoretical and practical implications of adopting mono-causal, multi-factorial, or integrated causation frameworks in cancer epidemiology, and their influence on prevention and policy strategies.

• Interventions: Assessment of how evolving etiological models should shape population health interventions, resource allocation, screening guidelines, and communication strategies.

• Social Inequalities and Early-Onset Cancers: Investigations into how social determinants (such as socioeconomic status, access to healthcare, education, occupational exposures, and experiences of discrimination) influence the risk, detection, treatment outcomes, and survival of early-onset cancers.

This Research Topic aims to foster interdisciplinary dialogue on the mechanisms, exposures, and risk factors that underlie the emergence and rising burden of early-onset cancers, illuminate the interplay and possible tension between mono-causal and multi-factorial approaches to cancer causation, especially as they relate to policy development and effective prevention strategies, and encourage research that identifies critical life-course windows of vulnerability, clarifies the mechanistic pathways linking exposures to disease, and disentangles the unique versus shared characteristics of early- and late-onset cancers.

Are you interested in contributing a manuscript to this Research Topic?

Early-Onset Cancers: Implications of Epidemiological Trends and Underlying Causes