Rethinking the rise of early onset gastrointestinal cancers: a call to action.

Since the early 1990s, there has been a dramatic rise in gastrointestinal cancers diagnosed in patients under age 50 for reasons that remain poorly understood. The most significant change has been the increase in incidence rates of early-onset colorectal cancer, especially rates of left-sided colon and rectal cancers. Increases in gastric, pancreatic, and other gastrointestinal cancer diagnoses have further contributed to this trend. We formed a multidisciplinary Think Tank to develop a strategic, coordinated approach to studying early-onset gastrointestinal cancers. This area of research is challenging given multifactorial etiologies. We focused on epidemiology and the environment, the microbiome, and survivorship as key pillars to structure a research framework. We advocate a comprehensive strategy to 1) utilize existing biospecimens, especially those collected longitudinally, with correlation to exposures ("the exposome"), 2) standardize microbiome specimen collection and analyses of blood, tissue, and stool specimens to minimize contamination and biases, 3) prioritize mechanistic studies to evaluate findings from biomarker studies, and 4) explore the unique survivorship needs of this young population. These recommendations build upon prior efforts with the goal of streamlining research into this important field of study while minimizing redundant efforts. We hope that our findings serve as a clarion call to motivate others to discover why young individuals are being diagnosed with gastrointestinal cancers at such an alarming rate and how to best support those who have been diagnosed.