Intestinal flora characteristics of advanced non-small cell lung cancer in China and their role in chemotherapy based on metagenomics: A prospective exploratory cohort study

Background Lung cancer has the highest mortality rate among malignant tumors, with non-small cell lung cancer (NSCLC) being the most common type. As the main component of the human microflora, the intestinal flora interacts with the human body to affect immunity, metabolism, and the formation of diseases. Methods Forty-five patients with advanced NSCLC who received platinum-containing dual-drug chemotherapy were enrolled in a prospective exploratory cohort study. The intestinal flora was dynamically collected at baseline and after two chemotherapy cycles. Next-generation sequencing and metagenomics were then used to analyze the species and function of the intestinal flora at all levels. Results Significant differences in the intestinal flora of patients with NSCLC were found according to sex and age. At the family level, the abundances of Streptococcaceae, Lactobacillaceae, and Leuconostocaceae after platinum-containing dual-drug chemotherapy were significantly higher compared to those before chemotherapy. At the family level, patients with chemotherapy-induced gastrointestinal reactions had a significantly higher abundance of Leuconostocaceae than those without gastrointestinal responses. Meanwhile, patients with gastrointestinal reactions had higher metabolism, human diseases, cellular processes, and environmental information processing than those who did not. At the genus level, responders had higher abundances of Bacteroides compared to nonresponders. Moreover, nonresponders had higher levels of the six major metabolic pathways compared to responders. Conclusions The intestinal flora of Chinese patients with advanced NSCLC differed according to sex and age. Moreover, significant differences in the intestinal flora were noted after chemotherapy, which could be associated with chemotherapy-induced gastrointestinal reactions and the efficacy of chemotherapy.