Literature ReviewA 2015 survey of nutritional approaches to prostate cancer published in BMC Medicine contains a table of approaches for which the authors found research. See table 1 in [Full Free Text of paper].
UK NCRN POMI-T StudyA 2014 six month randomized placebo-controlled double blind UK study published in Prostate Cancer and Prostatic Diseases of a mixture of polyphenols (pomegranate, green tea, turmeric and brocolli) with 199 prostate cancer patients on Active Surveillance or Watchful Waiting found that the treatment arm had an increase in PSA of 14% vs. 79% for the control arm (lesser increase is more favorable). The paper notes that the study received no funding from the manufacturer of the supplement. [Full Free Text of Paper] [Cancernet UK Charity info] [video interview with researcher Robert Thomas] [Manufacturer's FAQ].
PSA Doubling Time. Note that a 14% increase in PSA over a 6 month period (as found in the treatment arm) represents a doubling time of 6 / log2(1.14) = 31.74 months whereas an increase of 79% over 6 months (as found in the control arm) represents a doubling time of 6 / log2(1.79) = 7.14 months. Thus the doubling time was 31.74 / 7.14 = 4.4x times longer in the treatment arm (higher is more favorable).
Disease Progression. MRI scans were not part of the protocol but many of the patients had them anyways as part of their routine medical visits and these scans were consistent with lesser disease progression in the treatment arm (as opposed to just a matter of just modifying the PSA kinetics).
Group Composition. The treatment and control groups were assigned randomly subject to assigning 2 patients in the treatment group for every patient in the control group. By chance the average age in the treatment group was 5 years less than the average age in the control group so statistical methods were used to adjust the results to correct for this difference. On other measured variables the two groups were statistically similar.
A 12 month US study on effects of pomegranate extract on rising PSA levelsA randomized double blind trial of pomegranate extract on 183 men with rising PSA after primary therapy published in Prostate Cancer and Prostatic Disease 2015 found no effect on PSA doubling time. It did find some indications that patients with the MnSOD AA genotype might benefit but this would require a further study to confirm. Some of the study authors received funding from the manufacturer of the extract. See [PMID: 26169045] [Full Free Text].
Key differences between this study and the UK NCRN POMI-T study are that:
- this study was performed after primary therapy whereas the UK study was performed on patients undergoing Active Surveillance and Watchful waiting.
- this study examined only pomegranate extract whereas the prior study examined pomegranate extract in combination with 3 other polyphenols.
- this study followed men for one year and the UK study for 6 months