Androgen‐Deprivation Therapy and Dietary Habits Influence the Gut Microbial Environment in Patients With High‐Risk Localized Prostate Cancer

Background The aim of this study is to investigate the relationship between the gut microbial profiles, occurrence of side effects, total testosterone (TS) levels, and pretreatment dietary habits among patients with high‐risk localized prostate cancer who were subjected to androgen‐deprivation therapy (ADT). Methods This prospective study included patients diagnosed with high‐risk localized prostate cancer who underwent ADT between March 2021 and August 2022. The correlation between the pre‐ and post (after 3 months)‐ADT gut microbial profiles, laboratory tests, body consumption data, and pretreatment dietary habits was analyzed. Results No significant differences were observed in the alpha‐ and beta‐diversities of the gut microbiota during pre‐ and post‐ADT. The relative abundance of genus Ruminococcus 2 ( p = 0.013) and genus [ Eubacterium ] ruminantium group ( p = 0.043) were significantly higher during post‐ADT compared with those during pre‐ADT. Twenty percent of the patients with a post‐ADT TS level of < 20 ng/dL had a significantly high proportion of genus Ruminococccus 2, whereas no significant proportion was observed in patients with a TS level of ≥ 20 ng/dL. In terms of the impact of the pretreatment dietary habits on the changes of the gut microbiota, genus Romboutsia and genus Fusicatenibacter showed a positive correlation with n‐6 polyunsaturated fatty acid intake, whereas the amounts of genus Ruminococcus 2 and genus Veillonella showed a negative correlation with n‐3 polyunsaturated fatty acids. Conclusions Short‐term ADT was found to increase the proportion of gut genus Ruminococcus 2 in patients with advanced prostate cancer, which was associated with low TS levels and showed a negative correlation with n‐3 polyunsaturated fatty acid intake. Further validation is important to identify specific changes in the gut microbiota during ADT in patients with prostate cancer.