Gut health and prostate cancer: The influence of a specific phytochemical-rich food capsule plus or minus a probiotic/prebiotic blend on symptoms and progression—A randomised, double-blind placebo-controlled trial.

311 Background: The "gut-prostate axis" is increasingly being recognised as an influencer of prostate cancer (PCa) incidence and progression via its affect on inflammation, oxidative stress and immune surveillance. Murine models have shown that improving the gut microbiome can slow cancer progression. Boosting phytochemical rich foods (PRF) has previously been shown to inhibit Prostatic Specific Antigen (PSA) progression in men with indolent PCa and are potent prebiotics, working in synergy with lactobacillus probiotics, and vitamin D. Until now, no study has evaluated this dietary combination in men with PCa. Methods: 212 men with PSA progressing PCa (average age 74.5 years) managed with surveillance were given a Phytochemical Rich Supplement (PRS), uniquely containing both standardised extracts and whole purified organic ginger, cranberry, pomegranate, turmeric, broccoli and green tea. Men were then randomised (1:1) to a placebo (P) or a Probiotic blend (PB) of 5 lactobacillus probiotics with prebiotic inulin and vitamin D, for 16 weeks. Results: For the 105 men on PRS+P, the average rate of PSA rise pre to post baseline changed from 19.6% to 6.2% - a statistically significant (SS) reduction of 13.4% (a paired t-test p<0.01). For the 107 men on PRS/PB, the rate changed from a 21.7% rise to a 20% fall - a reduction of 41.7% (p<0.0001). There was a SS greater difference in PSA dynamics comparing the PRS+BP v PRS+P groups (28.3%, p<0.0001).The International Prostate Symptom Score and the International Index of Erectile Function were SS better in the PRS+PB v PRS+P men (10.5 v 14.1; 26.6 v 23.7 respectively, both P<0.001). Both arms had good tolerance, 5% had some bloating but conversely 14% reported improved gut symptoms. There was no difference in testosterone levels. Pre and post MRI was available in 180 men to date. In 10, the disease was reported to shrink, 164 stabilised and 6 worsen with PSA progression at a higher than average rate in all these 6, suggesting no PSA masking effect. Conclusions: This new phytochemical rich food supplement significantly slowed PSA progression, improved urinary symptoms and erectile function in men with indolent PCa. In addition, this is the World's first double blind RCT to demonstrate that an intervention aiming to improve gut health using pre and probiotics further reduced PSA progression. Hopefully, these findings will encourage more microbiome related research in men with PCa. Further follow up will determine whether this slowing of PSA progression influenced men's decision to avoid the toxicities of radical interventions. MRI images, so far, are reassuring but longer follow up is also planned. This evidence based information, will help dietary choices and will be welcomed by men on surveillance, with whom this trial was designed. Clinical trial information: 81939514.