PSA doubling time was prolonged in men who had biochemical failure after surgery or radiotherapy.
Pomegranate juice may help slow progression of prostate cancer in men who experience rising PSA levels following radical prostatectomy or radiotherapy, data suggest.
Researchers at the University of California at Los Angeles (UCLA) presented long-term data from a phase 2 trial involving 48 men who had rising PSA levels after prostate cancer treatment.
To be eligible for the study, subjects had to have a PSA level greater than 0.2 ng/mL but less than 5. The men had a pretreatment Gleason score of 7 or less. Participants drank eight ounces of pomegranate juice daily (570 mg total polyphenol gallic acid equivalents).
Interim results previously published in Clinical Cancer Research (2006;12:4018-4026) showed a significant increase in the mean PSA doubling times after treatment with pomegranate juice: from 15 months at baseline to 54 months post-treatment.
Following these positive results, the study was amended to allow subjects to continue treatment and undergo evaluation at three-month intervals until disease progression. At the end of six years, the mean PSA doubling time was 60 months post-treatment, according to investigators.
In the sixth year of treatment, 15 patients (31%) remained in the study, with a median follow-up of 30 months post-treatment (maximum 64 months). These patients had a significantly greater PSA doubling time and larger decline in median PSA slope than subjects no longer in the study.
“We are now in the seventh year of this study. This is quite unique in clinical research—to have such a long length of follow-up in a phase 2 study,” said lead investigator Allan Pantuck, MD, Associate Professor of Urology at the David Geffen School of Medicine at UCLA.
“We have preclinical and clinical data that continue to suggest a slowing down of PSA doubling times in patients with prostate cancer.” The effect of pomegranate juice on PSA doubling times appears to be durable, he said.
Dr. Pantuck noted that the trial so far suggests that daily consumption of pomegranate juice for more than five years appears to be safe and to produce no untoward adverse effects. In addition, data show that some patients may be more sensitive than others to the effects of pomegranate juice.
He pointed out that promegranate juice is being studied for many medical indications— “everything from cancer to heart disease. However, it is still too early to say it is an elixir of life or that we have proven that there is a benefit. We currently have positive results that have justified the time and expense and effort to study the juice in a phase 3 study, and we hope to have these definitive results shortly.”
“This study suggests that pomegranate juice may effectively slow the progression of prostate cancer after unsuccessful treatment,” said AUA spokesperson Christopher Amling, MD, Division Chief of Surgery at Oregon Health & Science University in Portland.
“This finding and other ongoing research might one day reveal that pomegranate juice is an effective prostate cancer preventative agent as well.”