Gut Microbiome as a Lifestyle Risk Factor Associated with Prostate Cancer.

[BACKGROUND AND OBJECTIVE] Most prostate cancer prevention strategies suggest lifestyle modifications, which lack personalization. Gut microbiome is increasingly recognized as an influencing factor in nongastrointestinal cancers, including prostate cancer. The use of gut microbiome as a lifestyle biomarker could help identify individuals with lifestyle more prone to prostate cancer and allow for modification. We aimed to develop a gut microbiome-based biomarker derived from patients undergoing prostate cancer screening.

[METHODS] We assessed whether the future cancer risk can be evaluated based on a microbiome risk analysis. After extracting DNA, sequencing, and performing a bioinformatics analysis, we identified 39 unique microbial genera of importance. We utilized an artificial intelligence model to calculate their presence, abundance, and weighted significance, generating a microbiome score (Prostate Cancer Risk Insight using Microbiome UnderStanding [PRIMUS]) that ranges from 0 to 1.

[KEY FINDINGS AND LIMITATIONS] Men with an increasing PRIMUS signature showed a sequential increase in prostate cancer risk. The prostate cancer risk persisted after a median follow-up of 4.5 yr. As a risk-assessment tool, the microbiome score compared favorably with prostate cancer risk calculators. Study limitations include the use of two patient groups to diversify the population for both a screening and a prebiopsy scenario; however, the cohorts used different collection methods, including stool, rectal swabs, and glove tip samples, but the same DNA isolation and sequencing. We relied on the longitudinal approach to help reduce these initial differences.

[CONCLUSIONS AND CLINICAL IMPLICATIONS] The gut microbiome may serve as a lifestyle risk factor for prostate cancer, but it is not intended to guide biopsy decisions. The implications of this study hinge on the potential for modifiability of the microbiome that could be tested in future clinical trials on prostate cancer risk reduction.