Does pomegranate play role in management of biochemically recurrent prostate cancer?
Pomegranate juice and extract are safe but do not favourably influence outcomes in prostate cancer patients with biochemical recurrence (BCR), a study has shown. However, a subset of BCR patients with the manganese superoxide dismutase (MnSOD) AA genotype appear to respond positively to the antioxidant effects of pomegranate.
With the aim of determining whether pomegranate products could slow the growth of prostate cancer, researchers conducted a review of trials involving patients on active surveillance, patients receiving neoadjuvant treatment, patients with BCR after local prostate cancer therapy, and patients with metastatic castration-resistant prostate cancer (mCRPC).
Data from early phase II trials in a BCR patient population showed that both pomegranate juice and extract significantly prolonged prostate-specific antigen (PSA) doubling time (PSADT), confirming the safety of pomegranate products.
In a placebo-controlled phase III trial, on the other hand, although pomegranate extract did not significantly lengthen PSADT in BCR patients, a preplanned subset analysis of patients with the MnSOD AA genotype demonstrated notable PSADT lengthening in the pomegranate extract arm.
Meanwhile, a large trial conducted in a neoadjuvant population found a substantial increase in urolithin A and a nonsignificant reduction in 8-hydroxy-2-deoxyguanosine, a marker of oxidation in prostate cancer tissue, in the pomegranate vs the placebo arm.
Furthermore, a randomized clinical trial of a polyphenol-rich multicomponent food supplement containing 31.25 percent pomegranate extract reported a significant slowing of PSA increase in the food supplement arm vs placebo in patients on active surveillance and those with BCR.
Preclinical studies showing that pomegranate juice and its components inhibit prostate cancer have reported that 90 percent of the antioxidant activity of the fruit is provided by the punicalagins and other hydrolysable tannins derived from pomegranate. [J Agric Food Chem 2000; 48: 4581–4589]
“Patients asking about pomegranate juice or extract consumption should be referred to the Prostate Cancer, Nutrition, and Dietary Supplements–Patient Version at the National Cancer Institute, where they will find brief summaries of the source of bioactive compounds in pomegranates, and the results of preclinical studies and clinical trials in the biochemically recurrent prostate cancer patient population, concluding with the phase III trial results showing no differences in PSADTs between placebo and pomegranate arms,” researchers said.
They added that if the beneficial effect of pomegranate products in patients with the MnSOD AA genotype is confirmed in future studies, testing for MnSOD status may be beneficial in guiding patients.