Implications of intestinal microecology and immune function alterations for immunotherapy outcomes in advanced unresectable lung adenocarcinoma

Objective This investigation aims to explore alterations in intestinal microecology and immune function among patients with advanced, unresectable lung adenocarcinoma undergoing different outcomes from immunotherapy. Methods A cohort of 30 patients diagnosed with advanced unresectable lung adenocarcinoma received sintilimab immunotherapy as a monotherapy. Post four treatment cycles, efficacy was assessed, leading to the segregation of patients into two distinct cohorts: those responsive to treatment and those nonresponsive. Analysis involved observing variations in the abundance, distribution, and composition of fecal intestinal microorganisms pretreatment and posttreatment via 16S rRNA gene sequencing. Results In this study involving 30 advanced lung adenocarcinoma patients, significant observations were made regarding the impact of immunotherapy on immune function and the gut microbiome composition. Patients were divided into treatment and control groups, revealing that immunotherapy led to a significant increase in CD4+ T cells and a decrease in CD8+ T cells among the treatment‐responsive individuals, indicating an enhanced immune response. Furthermore, an in‐depth analysis of the gut microbiome showed an increase in diversity and abundance of beneficial bacteria such as Faecalibacterium and Subdoligranulum in the treatment group. These findings highlight the dual effect of immunotherapy on modulating immune function and altering gut microbiome diversity, suggesting its potential therapeutic benefits in improving the health status of patients with advanced lung adenocarcinoma. Conclusion The structuring of gut flora plays a pivotal role in augmenting the efficacy of anti‐tumor immunotherapy, underscoring the interplay between intestinal microecology and immune response in cancer treatment outcomes. Venn diagram illustrating the distribution of OTUs. Each color represents a different sample. The investigation produced a total of 2705 operational taxonomic units (OTUs), with 2595 remaining after normalization. Within these, 146 OTUs were identified in MYA1, 58 in MYA2, 86 in MYB1, and an elevated number of 462 in MYB2, totaling 748 OTUs across all groups.