Allostatic load as a framework for understanding early-onset colorectal cancer: current biomarker evidence and future directions.

Introduction: Colorectal cancer incidence rates have been on the decline over the past 50 years due to increased screening and diagnostic tools. Over the past 32 years (since 1994), there has been a rise in colorectal cancer for those under 50 years old. This trend has been designated as early-onset colorectal cancer (EOCRC) and is in direct opposition to the decline seen in those over 50 years of age; designated as late onset colorectal cancer (LOCRC). The rise in EOCRC has been attributed to various factors such as environmental, modern diet and lifestyle. Methods: The paper includes a comprehensive search of both cohort and case-control studies that were designed to investigate the association between EOCRC and allostatic load (AL) using two databases: MEDLINE PubMed and Stony Brook University Libraries Database. Results: 12 studies were included in this paper. These papers varied on how many used biomarkers that are measured in allostatic load. Out of the 12 studies, only 3 had direct measurements of AL such as metabolic and cardiovascular, 9 measured indirect biomarkers such as inflammatory pathways and epigenetics. Conclusion: The purpose of this paper is to change the current paradigm focus of the causation of EOCRC being associated with a single factor and instead study factors together using allostatic load. Although none of the papers measured AL and EOCRC directly, they each used a direct or indirect measurement of AL when studying EOCRC. We believe that AL should be the next focus for future research of EOCRC to better understand how all these factors contribute to disease progression.