The two-stage clinical trial tracked 48 men over six years who had had rising prostate specific antigen scores after surgery or radiation. They were told to drink eight ounces of pomegranate juice daily.
The decline in median PSA slope was greater among those still drinking the juice after six years compared to a "non-active" group that had begun with similar baseline PSAs.
Researchers from the David Geffen School of Medicine, at the University of California, Los Angeles, and the Rambam Medical Center in Haifa, Israel, presented the findings at the annual scientific meeting of the American Urological Association in Chicago.
"This study suggests that pomegranate juice may effectively slow the progression of prostate cancer after unsuccessful treatment," Dr. Christopher Amling, spokesman for the American Urological Association, said in a statement. "This finding and other ongoing research might one day reveal that pomegranate juice is an effective prostate cancer preventative agent as well."