Pomegranate Juice May Slow Prostate Cancer

Pomegranate juice may slow the progression of prostate cancer, according to long-term research results recently presented at the 104^th Annual Scientific Meeting of the American Urological Association.

One of the screening tests used for finding prostate cancer early is the PSA test. PSA stands for prostate-specific antigen, a protein that's produced by the prostate gland. Normally, men have a low level of PSA in their blood, but prostate cancer (as well as relatively benign conditions like benign prostate hyperplasia (BPH) and prostatitis) can increase the levels substantially. Researchers frequently track the increase in PSA as an indicator of how quickly a cancer may be growing. "A very long doubling time is a good thing", explained Christopher Amling, MD, a spokesman for the American Urological Assocation. "A very rapid doubling time is a surrogate marker for mestatizing. The shorter the doubling time, the more rapidly the cancer is growing".

In this study, researchers studied men who had been treated for prostate cancer with either surgery or radiation and monitored the "success" of the treatment by watching how long it took for their PSA's to double. They studied 48 men who had an average "doubling time" of 15 months at the beginning of the study. The men were given 8 ounces of pomegranate juice daily.

The study began in 2003 and is now in its sixth year. When researchers recently compared men who dropped out of the study with men who are still participating, they found that the active patients now had an average doubling time of 54 months. An earlier paper (in Clinical Cancer Research, 2006(1)) showed that about 1/3 of the men treated with pomegranate juice actually experienced a decline in their PSA, while 83% of the men showed a lengthening of their PSA doubling time, indicating that the growth of the cancer had significantly slowed. The current paper presented at the Urological Society is an update of the ongoing research, and confirms the positive results. "The average doubling time is now closer to 60 months", Dr. Amling told me.

The researchers don't know exactly what compounds found in pomegranate juice are responsible for the results. "We think it's the polyphenol antioxidants", Dr. Amling told me, "but we haven't tried to isolate any one compound". He told me that while some researchers are trying to isolate the active ingredients, the individual ingredients themselves don't seem to work as well as the actual juice which contains dozens of plant based chemicals that may have a synergistic effect.

Does this mean that pomegranate juice can prevent prostate cancer? That's a claim no responsible researcher is willing to make- yet- though it certainly appears to have anti-cancer activity. "Pomegranate juice looks very promising as a non-toxic strategy for slowing the progression of prostate cancer", Dr. Amling said. "For a significant number of people, the benefits are enormous and durable".

The study used Pom Wonderful, a widely available brand of Pomegranate Juice.

REFERENCES

1. Pantuck, et al "Phase ll Study of Pomegranate Juice for Men with Rising Prostate-Specific Antigen following Surgery or Radiation for Prostate Cancer", Clin Cancer Res 2006 Jul 1: 12 (13): 4018-26
   
2. 104^th Annual Scientific Meeting of the American Urological Assocation, April 25-30, Chicago Ill (http://www.medscape.com/viewcollection/30211)
   

Green Tea and Prostate Cancer

Prostate cancer is one of the most common types of cancer found in American men and it is estimated that 1 man in 6 will get prostate cancer during his lifetime.

A new study investigated the effects of a botanical antioxidant in subjects with prostate cancer. The botanical antioxidant? Green tea extract.

In this new study, 26 men with confirmed prostate cancer were given a supplement of green tea constituents. The supplement contained a total of 1.3 grams of green tea polyphenols, which included 800 mg of epigallocatechin-3-gallate (EGCG) and lesser amounts of epicatechin, epigallocatechin, and epicatechin-3-gallate.

The men received the green tea supplement until the time of their radical prostatectomy surgery, averaging a supplementation period of 34.5 days.

Blood tests were performed at the beginning of the study and again on the day of surgery. The blood tests included:

• prostate-specific antigen (PSA), a test commonly performed to monitor prostate health
  
• hepatocyte growth factor (HGF) which is a factor that regulates cell and tumor growth
  
• vascular endothelial growth factor (VEGF) which is a signaling protein believed to influence cancer progression
  
• insulin-like growth factor (IGF)-I which is a protein that has been shown to play a role in the development of cancers
  
• IGF binding protein-3 which regulates the activity of IGF
  
• liver function tests to monitor possible toxicity.
  
• In addition, cancer-associated cells known as fibroblasts were treated in vitro with EGCG and were tested for HGF and VEGF.
  

The study showed a significant reduction in the levels of the serum cancer biomarkers HGF, VEGF, PSA, and liver enzymes in the test subjects after treatment with the green tea supplement. Additionally, some patients demonstrated reductions in levels of these biomarkers greater than 30 percent. The in vitro study of the fibroblasts showed a decrease in the production of HGF and VEGF as well.

The researchers concluded that the findings support a potential role for green tea "in the treatment or prevention of prostate cancer."

Reference:

McLarty J, Bigelow RL, Smith M, Elmajian D, Ankem M, Cardelli JA. Tea Polyphenols Decrease Serum Levels of Prostate-Specific Antigen, Hepatocyte Growth Factor, and Vascular Endothelial Growth Factor in Prostate Cancer Patients and Inhibit Production of Hepatocyte Growth Factor and Vascular Endothelial Growth Factor In vitro. Cancer Prev Res (Phila Pa). 2009 Jun 19. Published Online Ahead of Print.

Carbohydrate Restriction May Slow Prostate Tumor Growth

Restricting carbohydrates, regardless of weight loss, appears to slow the growth of prostate tumors, according to an animal study recently published by researchers in the Duke Prostate Center.

"Previous work here and elsewhere has shown that a diet light in carbohydrates could slow tumor growth, but the animals in those studies also lost weight, and because we know that weight loss can restrict the amount of energy feeding tumors, we weren't able to tell just how big an impact the pure carbohydrate restriction was having, until now," said Stephen Freedland, M.D., a urologist in the Duke Prostate Center and lead investigator on this study.

The researchers believe that insulin and insulin-like growth factor contribute to the growth and proliferation of prostate cancer, and that a diet devoid of carbohydrates lowers serum insulin levels in the bodies of the mice, thereby slowing tumor growth, Freedland said.

The findings appear in the May 26, 2009 online edition of the journal Cancer Prevention Research.

Animals in the study were fed one of three diets:

1. a very high fat/no carbohydrate diet
   


2. a low-fat/high carbohydrate diet
   


3. and a high fat/moderate-carbohydrate diet, which is most similar to the "Western" diet most Americans eat, Freedland said.
   

They were then injected with prostate tumors at the same time.

"The mice that were fed a no-carbohydrate diet experienced a 40 to 50 percent prolonged survival over the other mice," Freedland said.

Mice on the no-carbohydrate diet consumed more calories in order to keep body weights consistent with mice on the other study arms.

The researchers plan to begin recruiting patients at two sites – Duke and the University of California - Los Angeles - for a clinical trial to determine if restricting carbohydrate intake in patients with prostate cancer can similarly slow tumor growth. The trial should begin within a few weeks.

"It's very exciting - this is a potential new mechanism to fight prostate cancer growth and help patients live longer with their disease," Freedland said.