Dietary Quality and Microbiome Profiles among Rectal Cancer Patients: A Cross-Sectional Pilot Study

Area of Science:

• Microbiome research
• Nutritional science
• Gastroenterology

Background:

• Neoadjuvant chemoradiotherapy (nCRT) for rectal cancer (RC) can impact gut microbiota.
• Dietary quality is a crucial factor in patient outcomes and treatment response.
• Understanding the interplay between gut bacteria, diet, and treatment is essential for optimizing patient care.

Purpose of the Study:

• To investigate the correlation between gut microbial composition and predicted functional pathways with dietary quality scores in RC patients post-nCRT.
• To identify specific bacterial species and metabolic pathways, particularly those involved in B-vitamin biosynthesis, that differ based on dietary quality.

Main Methods:

• Stool samples from 30 RC patients were analyzed using 16S rRNA gene sequencing.
• Shallow shotgun metagenomics sequencing (SMS) was performed on a subset (n=17) for pathway validation.
• Dietary quality was assessed using the Prime Diet Quality Score (PDQS).

Main Results:

• Positive correlations were observed between higher PDQS scores and the abundance of genera like Parvimonas and Caproiciproducens.
• Negative correlations were found with genera including Prevotella and Enterococcus.
• Predicted B-vitamin (e.g., B5/pantothenate) and cofactor biosynthesis pathways, especially vitamin B5-CoA, were associated with higher dietary quality.

Conclusions:

• Significant associations exist between gut bacterial taxa, predicted B-vitamin biosynthesis pathways, and dietary quality in RC patients after nCRT.
• Specific bacterial species involved in vitamin B5-CoA biosynthesis were more prevalent in participants with high dietary quality.