Identifying the Primary Driver of Rising Cancer Incidence—A Path to Prevention

Cancer incidence has risen sharply over the past century. Despite enormous investments in cancer research and treatment, cancer continues to inflict immense human suffering and premature mortality. If current trends continue, nearly half of the populations in developed countries will develop cancer during their lifetime by 2040. Given the persistent challenges in treating solid tumors that cannot be surgically removed, primary prevention has become more imperative than ever. Effective prevention, however, requires a clear understanding of the primary driver behind the dramatic rise in cancer incidence. Identifying this driver has been difficult because numerous risk factors may contribute to carcinogenesis directly or indirectly. To overcome this challenge, this study focuses on what has primarily driven the increase in cancer incidence rate over the past eight decades, rather than what causes cancer. To achieve this objective, the present study classified all potential root causes into six categories—genetics, aging, lifestyle, nutrition, psychological stress, and environmental exposures—and evaluated their biological mechanisms, exposure scales, and probabilistic dependencies (temporal correlations) in relation to the increase in cancer incidence rate. Based on established criteria for causal inference, this study finds that the chronic accumulation of toxic chemicals in the human body through food, water, air, and consumer products applied to the skin is most likely the principal driver of the escalating incidence of cancer over the past century. Therefore, reversing this upward trend will require public health policies that prioritize reducing exposure to these ubiquitous toxic chemicals.