Abstract 1237P
Background
The gut microbiome affecting clinical responses to cancer therapy has been demonstrated. However, considering targeted therapy and chemotherapy, its relevance remains unknown. This study aimed to explore the relationship between the gut microbiome and clinical outcomes in Thai advanced NSCLC patients (pts) according to EGFR status.
Methods
Thirteen EGFR-WT advanced NSCLC pts treated with chemotherapy and 15 EGFR-mutant pts treated with EGFR-TKIs were enrolled in this study. Fecal samples were collected at baseline and at first disease evaluation. 16s rRNA gene sequencing by NGS was applied to assess our microbiota profile. Gut microbiome and clinical correlations were explored.
Results
The clinical characteristics were balanced between the 2 cohorts, except high albumin level was significantly higher in EGFR-mutant group. Albumin was the only significant clinical factor affecting the treatment response in multivariate analysis (ORR=15.6, P = 0.03). Proteobacteria was higher in EGFR-WT group while Bacteriodota and Firmicutes were higher in EGFR-mutant group. EGFR-mutant pts significantly harbored higher alpha diversity of gut microbiome at baseline compared to EGFR-WT pts (Shannon index 3.82 VS 3.25, P = 0.022). Proteobacteria was decreased, but Bacteroidota and Firmicutes were increased after treatment in both cohorts but it was prominent in EGFR-WT cohort. There was no significant correlation between microbiome profile and treatment response in our study. However, beta diversity of microbiota was significantly different in pts with different severity of adverse events (AEs). Enrichment of Clostridia and Bacteriodia were associated with higher AEs in EGFR-WT cohort.
Conclusions
EGFR+ve NSCLC pts had significantly higher gut microbiome composition and alpha diversity from those who had EGFR-WT. Proteobacteria was dominate in lung cancer pts and may be associated with lung cancer carcinogenesis. Chemotherapy altered the gut microbiota whereas EGFR-TKIs showed less alteration between pre and post treatment. There was no association between microbiota and treatment response. Microbiota may be used as biomarker for lung cancer in the future. Larger cohort studies should be conducted.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Thailand Center of Excellent for Life Science (TCELS).
Disclosure
All authors have declared no conflicts of interest.