I saw this (pdf):
Intensive Lifestyle Changes May Affect The Progression Of Prostate Cancer, The Journal of Urology, 2005
Men (n=93) with early, biopsy-proven prostate cancer were randomly assigned to one of two groups:
Control Group (n=49):
- Did not plan to undergo any conventional treatments (6 did owing to cancer progression).
- Employed lifestyle changes (diet, exercise, stress management) recommended by their physicians.
- Did not plan to undergo any conventional treatments (none did).
- Vegan diet (no meat, fish, dairy, eggs), low-fat*, minimal simple and refined carbohydrates.
- Soy beverage daily.
- Fish oil (3 grams) daily.
- Vitamin E (400 IU) daily.
- Vitamin C (2 grams) daily.
- Moderate aerobic exercise (30-minute walks) 6 times/week.
- Stress management (stretching, meditation, imagery, progressive relaxation) 1 hour daily.
- Support group weekly.
Findings, after 1 year:
- Prostate Specific Antigen (PSA) decreased 4% in treatment group, increased 6% in the control group. (The gap between groups may have been greater since 6 control group patients opted for conventional treatment before the end of the study, owing to increasing PSAs, and their values were not included.)
- The growth of LNCaP cancer cells* was inhibited almost 8 times more by serum from treatment vs. control group participants.
- Levels of testosterone and C-reactive protein (a marker for inflammation) did not differ between groups.
The diagram to the right, top, shows mean changes in PSA between groups after 1 year. (P=0.016)
The diagram to the right, bottom, shows mean changes in LNCaP cancer cell growth between groups after 1 year. Something in the serum of the men in the treatment group inhibited the growth of prostate cancer cells 8 times more than serum of men in the control group. This suggests that tumor growth, as well as PSA (which is just a marker for tumor growth), can be slowed by lifestyle changes.
This study is difficult to parse because the treatment group was exposed to a number of interventions simultaneously. However, as with other lifestyle interventions I've been reading about, multiple less-intensive changes can have an equivalent or even greater impact than single, more-intensive changes. There may be an additive, complementary, or synergistic effect.
What we do know from this study is that the comprehensive impact of the independent variables had a beneficial effect on the dependent variables. The pattern as a whole slowed the progression of prostate cancer in these men. We also know that benefit from adherence to the pattern was dose dependent, i.e. "the extent to which participants made changes in diet and lifestyle was significantly related to decreases in PSA and to LNCaP cell growth."
The photo above is an MRI showing prostate tumor activity diminishing after a year in a man who took part in this study. It's a screen capture of a video of Dr. Dean Ornish, lead author of the study. You can watch a 3-minute video of Dr. Ornish discussing lifestyle changes, including this study, here:
Update: See my next post for 4 mouse studies that support the benefits of a low-fat diet for prostate cancer.