Analysis of the fecal metagenome in pelvic radiation survivors with or without chronic gastrointestinal toxicity.

• DOI: 10.1200/jco.2024.42.16_suppl.e24041
• Publication Date: 2024-06-04T15:22:42Z
• Authors: Bailey Nelson; Senu Apewokin; Hope Esslinger; Jordan Kharofa
• Keywords: 03 medical and health sciences; 0302 clinical medicine

e24041 Background: Whole pelvis radiation therapy (WPRT) is often used as a definitive or adjuvant treatment in patients with genitourinary, gynecologic, and gastrointestinal (GI) malignancies. Irradiation of nearby bowel can cause acute chronic GI symptoms, which affect patients’ quality life. Radiation has been shown to alter the microbial flora may select for pathogenic species, enhance toxicity. Characteristics fecal metagenome without toxicity unknown. Severity symptoms vary between who receive similar dose normal bowel; therefore, there critical need evaluate interaction RT species development Methods: An institutional database was identify survivors that completed WPRT prostate, anal cancer within last 5 years. Patients were excluded if they had evidence recurrent disease requiring additional therapy. Eligible asked participate via telephone. Consenting provided stool sample customized PRO-CTCAE form (scale 1-5) assessing symptoms. Comprehensive shotgun metagenomics performed on stool. Stool sequenced using an Illumina NextSeq500. The compared. dichotomized by diarrhea score (0-1 [mild] vs ≥2 [moderate-severe]). Raw reads processed Kneaddata trimming, Kracken2 taxonomic profiling, Bracken abundance estimation bacterial, fungal viral genomes sequences from National Center Bioinformatics determine quantitative genus differences. For diversity assessments, estimated inverse Simpson Shannon indices performed. Results: Fecal results available 13 survivors. Thirty percent (n = 4) reported moderate severe diarrhea. mean age 66 years, 38% male, 46% received concurrent chemotherapy, time completion analysis 34 months (range 14-62 months). Conventional constraints met each patient. Several enriched mild Notably, Akkermansia muciniphilia largest differential enrichment Conclusions: In this cohort patients, A. muciniphilia, mucin-degrading bacteria modulates gut barrier integrity mucin layer thickness, no compared supplementation decrease systemic inflammation Western diet-fed mice. Evaluation radioprotective bacterium warrants further evaluation.