Exploring the Association Between Red and Processed Meat Intake and Colorectal Cancer (CRC) Tumor Markers: Case-only analyses based on 9 international studies

Abstract

Background:Colorectal cancer (CRC) is a heterogeneous condition with different pathways of carcinogenic development. Red and processed meat has been established as a risk factor of CRC, but epidemiological studies done so far to elucidate the association between red and processed meat and CRC tumor markers have been limited by sample size. Methods:In this study, we pooled data from 9 studies participating in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), and ran logistic and multinomial regression models to investigate the association between pre-diagnostic red and processed meat intake and CRC tumor markers individually (MSI status, CIMP status, BRAF and KRAS mutations) as well as 5 CRC subtype-defining tumor marker combinations. Results:We found modest associations between meat intake and individual CRC tumor markers. We noted significant inverse associations between being in quartile 3 (Q3) (vs. Q1) of red meat intake and CIMP-high tumors (ORadjusted = 0.84, 95% CI: 0.71-0.99), and between being in quartile 2 (Q2) (vs. Q1) of processed meat intake and KRAS-mutated tumors (ORadjusted = 0.84, 95% CI: 0.73-0.97). We also found significant associations between being in Q2 (vs. Q1) of red meat intake and CRC subtype 5 (ORadjusted = 1.51, 95% CI: 1.06-2.15) as well as between being in Q2 (vs. Q1) of processed meat intake and CRC subtype 3 (ORadjusted = 0.82, 95% CI: 0.68-0.98). Lastly, we noted no significant associations between red or processed meat intake and subtype 1 or 2. Conclusion:Our findings suggest modest associations between meat intake and CRC tumor markers with no discernable trends in associations with increasing or decreasing meat consumption levels. These findings indicate the need for more pooled analysis studies to better elucidate the associations of red meat intake with different pathways of CRC development.