Lower airway bacterial microbiome may influence recurrence after resection of early-stage non–small cell lung cancer

Objective: The lower airway bacterial microbiome influences carcinogenesis and response to immunotherapy in non–small cell lung cancer (NSCLC). We investigated the association of this microbiome with recurrence in early NSCLC. Methods: Microbiomes of presurgery bronchoalveolar lavage (BAL) and saliva, and resected stage I NSCLC tumor and adjacent lung tissues of 48 patients were examined by 16S gene sequencing. Tumor gene expression was measured by RNA sequencing. Results: Spatial relationships of the different biospecimen types was reflected in their microbiomes, with microbiomes of BAL intermediate to those of saliva and lung tissue. BAL and saliva microbiomes were less dissimilar in patients with high α-amylase levels in BAL, indicating oral aspiration as a source of lower airway microbiota. BAL microbiomes of patients with recurrence within 32 months of surgery differed from those without recurrence during ≥32 months of follow-up (n = 18 each), despite no difference for age, sex, smoking history, and tumor histology and grade. The recurrence-associated BAL microbiome signature was present in 16 of the 18 recurrence cases but in only two of the others. Signature presence was associated with shorter recurrence-free survival (log-rank test P < .001; hazard ratio = 14.5), and greater expression in tumors of genes for cell proliferation and epithelial mesenchymal transition. Immune cellular composition of the tumor microenvironment was not different between patients with and without the signature. Conclusions: Presurgery composition of lower airway microbiome may be associated with recurrence of early NSCLC. This association may reflect an influence of the microbiome on tumor biology.