73P Correlation between diet, microbiome composition and clinical outcomes in patients with non-small cell lung cancer

Immune checkpoint inhibitors (ICI) dramatically improved outcomes of patients with non-small cell lung cancer (NSCLC). The gut microbiome has emerged as a biomarker of response to ICI in NSCLC and a potential therapeutic target. High fiber and Mediterranean diets were associated with prolonged response in patients with melanoma treated with ICI. The objective of this study was to assess the effect of diet on outcome and microbiome composition. Prospective collection of clinical and dietary data were assessed in 102 patients with NSCLC amenable to ICI. We employed a standardize food frequency questionnaire (FFQ) specific to the NSCLC population designed by a clinical nutritionist. FFQ answers were recorded electronically and analyzed using a calculation tool to estimate the median daily fiber (g/day), and surrogate markers of the Mediterranean diet; Monounsaturated fatty acids (MUFA) and Polyunsaturated fatty acids (PUFA) intake (g/1000kcal). Then correlated with progression-free survival (PFS) and overall survival (OS). Microbiome was profiled in a sub-group of 76 patients using shot-gun metagenomic, MetaPhlan4 pipeline was used to detect species, diversity index and LefSe were calculated. Among the 102 patients with NSCLC the median fiber intake was 16 g/day and did not correlate with outcome. However, Spearman correlation showed a significant association between increased PUFA or MUFA intake and longer OS (p<0,001 and p<0,001). Moreover, MUFA dietary intake correlated with a prolonged PFS (median PFS high MUFA intake: 20.0 months versus low MUFA intake: 9.1 months, p=0.02). Additionally, MUFA and PUFA intake correlated with the increase abundance of Eubacterium, Alistipes and Bifidobacterium. In this cohort, patients had a very low fiber diet, however a high MUFA and PUFA intake was associated with beneficial response and an overrepresentation of known beneficial immunogenic bacteria. These results raise the possibility that evidence-based dietary recommendations counseling using educational tools may represent an important strategy to employ the gut microbiome as a potential therapeutic target in improving the response to ICI.