Gut Microbiota is Associated with Response to 131I Therapy in Patients with Papillary Thyroid Carcinoma

Abstract

Purpose Radioactive Iodine (131I) (RAI) therapy is a conventional post-surgery treatment widely used for papillary thyroid carcinoma (PTC). Since 131I is orally administered, we hypothesize that it may affect gut microbiome. This study aims to investigate alterations of intestinal microbiome after 131I therapy in PTC patients and explore its association with response to 131I therapy. Methods Fecal samples of 60 PTC patients pre- and post-131I therapy were collected to characterize the RAI-induced gut microbiota alterations using 16S rRNA gene sequencing. Sequence data of 40 out of the 60 patients, divided into excellent response (ER) group and non-excellent response (NER) group, were screened out to investigate the possible connection between gut microbiota and response to 131I. A random forest classifier for 131I response prediction was constructed. Results Microbial richness, diversity and composition were tremendously altered after 131I therapy. A significant decline of Firmicutes to Bacteroides (F/B) ratio was observed post-131I therapy. Some different metabolic pathways were found. Furthermore, discrepant β-diversity was found between the ER and NER groups pre- and post-131I therapy. A predictive classifier for response to 131I therapy with an AUC of 75.0% was constructed using four microbial variables-Bifidobacterium, Dorea, Erysipelotrichaceae, as biomarkers of ER and Parabacteroides, as biomarker of NER. Conclusion The present study illustrates the gut microbial dysbiosis after 131I therapy in PTC patients for the first time and reveals a previously undefined role of gut microbiome as potential biomarkers for predicting RAI responses.

Causal relationship between gut microbiota and differentiated thyroid cancer: a two-sample Mendelian randomization study

“…They developed a 10genus microbial signature capable of effectively distinguishing patients with DTC from healthy individuals. Moreover, the gut microbiota is closely associated with the therapeutic response to radioactive iodine (RAI) following thyroidectomy (13). Before RAI treatment, thyroid hormone withdrawal (THW) is typically necessary to stimulate the secretion of thyroid stimulating hormone; however, THW-related complications significantly decrease quality of life.…”