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(OR08-04-26) Diet-Derived Microbial Signatures in Gut and Tumor Tissue Predict Survival in Colorectal Cancer Patients

Sunday, July 26, 2026
9:06 AM - 9:18 AM ET
Location: Maryland Ballroom C
Disclosure(s):
Sushma Nepal, PhD Student: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: Identify gut and tumor-based microbial signatures linked to dietary patterns and evaluate associations with colorectal cancer (CRC) survival.

Methods: Study population consisted of two prospective cohorts. Dietary scores for the reversed Empirical Dietary Inflammatory Pattern (rEDIP), reversed Empirical Dietary Index for Hyperinsulinemia (rEDIH), and Alternate Healthy Eating Index-2010 (aHEI-2010) were calculated from baseline food frequency questionnaires in ColoCare participants with stool 16S rRNA sequencing (n=117). Participants with both diet and microbiome data are included in the study. Elastic-net models identified diet-associated microbial taxa and generated gut microbial profile scores. In ORIEN with RNAseq data, tumor microbial profiles were inferred from tumor RNA-seq (n=1,278) using the exotic pipeline. Gut-derived weights were applied to tumor microbial abundance estimates to compute diet-related tumor microbial profile scores. Multivariable Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for overall and CRC-specific mortality and for progression/recurrence outcomes.

Results: ColoCare participants were 72 (SD 12) years; 94% were White. Elastic net selected 60 taxa for rEDIH, 38 for rEDIP, and 77 for aHEI-2010. Higher rEDIH gut microbial profile scores reflecting higher dietary quality were associated with lower overall mortality (HR per 1-SD=0.58; 95% CI: 0.34, 0.98); rEDIP and aHEI-2010 scores were not significant. ORIEN participants were 55 (SD 12) years; 88% were White. Higher tumor microbial profile scores were associated with lower overall and CRC-specific mortality for rEDIH (HR per 1-SD=0.89; 95% CI: 0.81, 0.99) and rEDIP (HR per 1-SD=0.89; 95% CI: 0.80, 0.99), but not for aHEI-2010 (HR per 1-SD=0.94; 95% CI: 0.85, 1.05). No associations were observed for progression-free survival or recurrence.

Conclusions: Diet-related microbial profiles, particularly those linked to lower inflammation or lower insulinemia were associated with improved CRC survival.

Funding Sources: National Cancer Institute