Most of the reliable evidence for the effect of lifestyle on cancer progression comes from patients with indolent or relapsing prostate cancer. The slow growth rate in many patients and availability of a simple blood test (PSA) allows time for alternative interventions, making them acceptable to both clinician and motivated patients alike. The most well know study evaluated the benefits of pomegranate juice but the other published trials are summarised in this page .  

The pomegranate juice study  In this North American study, sponsored by the Pomegranate Growers Association, 48 men with prostate cancer were evaluated. Pomegranate juice has a particularly high concentration of antioxidants. All the patients had previously received radiotherapy or surgery but started showing evidence of their cancer returning in the form of a rising PSA blood test (generally referred to as PSA relapse). The rate of rise of the PSA for each patient was plotted on a graph and provided it rose in a consistent, steady fashion (i.e. not just a temporary increase), they were entered into the study. All men were given 200ml of pomegranate juice to drink everyday. The PSA blood test was then measured for several months and again plotted on the same graph. The rate of rise of the PSA (the doubling time – PSAdt) was compared before and after consumption of the juice.  There was a very significant prolongation of PSAdt, from a mean average of 15 months at baseline, to 54 months post pomegranate juice consumption. In other words this dietary intervention had slowed the growth rate of the tumour almost to a factor of four, which for men in their seventies may mean they would significantly delay or never need more aggressive hormonal intervention. For example, a man aged 74 years with a PSA of 3.5 and a PSAdt of 54 months would be 87 years old before his PSA exceeded 20.

             This study also had a further interesting angle. It looked at a factor known as the baseline oxidative state, which is thought to reflect the body’s ability to fight off the free radicals that cause cancer or encourage slow growing existing cancers to mutate into more aggressive counterparts. These free radicals are generated by eating unhealthy foods, excessive exposure to sunlight, smoking or radiation. Anti-oxidants mop up these free radicals before they have time to exert their damage. The optimal amount of anti-oxidants needed in the diet depends on the level of exposure to carcinogens as well as the individual’s own genetic makeup (i.e. vulnerability to attack). This balance of anti-oxidants and oxidative exposure can be measured in the blood with a variety of tools. The baseline oxidative state (BOS) was measured as a secondary end point in this study. Patients blood BOS significantly improved following pomegranate consumption when measured at the start, then at three separate points over the next year.

The lifestyle and vegan diet study. This involved a randomised study of 93 volunteers with early prostate cancer from the USA , who for various reasons had opted not to undergo conventional therapies. They were randomly assigned to intensive nutritional counselling and lifestyle changes, or simple active surveillance. In the 47 patients randomly assigned to lifestyle, they changed to a vegan diet supplemented with soy, vitamin E, fish oils, selenium and vitamin C. The physiotherapist guided them into a moderate exercise program requiring at least thirty minutes of walking six days a week. They also embarked on a number of stress management techniques such as yoga and massage. The PSA decreased at twelve months in the intervention group by 4%, but increased in the control group by 6%. When this difference was analysed independently by scientific statisticians, it was shown to be highly significant. In other words it was a difference, which was very unlikely to have occurred by chance (greater than 1:50 odds) – put another way; everyone believed it.

             The trial had another intriguing twist. A blood sample was taken from all patients at three monthly intervals. After removing the blood cells, the serum was added to sheets of living prostate cancer cells grown in culture dishes in a laboratory. Serum from the intervention group caused 70% of the laboratory prostate cells to stop growing, whereas serum from the control (non intervention group) only inhibited growth in 6% of cells. This eight-fold difference (70% v 6%) was highly significant and again statistically robust (fewer than 1:100 odds that it happened by chance). Furthermore, changes in PSA and cell line growth inhibition strongly correlated with the degree of lifestyle changes.

            This study also  looked at a factor known as the baseline oxidative state, which is thought to reflect the body’s ability to fight off the free radicals that cause cancer or encourage slow growing existing cancers to mutate into more aggressive counterparts. These free radicals are generated by eating unhealthy foods, excessive exposure to sunlight, smoking or radiation. Anti-oxidants mop up these free radicals before they have time to exert their damage. The optimal amount of anti-oxidants needed in the diet depends on the level of exposure to carcinogens as well as the individual’s own genetic makeup (i.e. vulnerability to attack). This balance of anti-oxidants and oxidative exposure can be measured in the blood with a variety of tools. The baseline oxidative state (BOS) was measured as a secondary end point in this study. Patients blood BOS significantly improved following pomegranate consumption when measured at the start, then at three separate points over the next year.

The broccoli study  Biologist at Britain 's Institute of Food Research published a study which showed that the healthy chemicals found in broccoli can prevent precancerous cells in the prostate progressing to more aggressive cancers. They found that just a few more portions of broccoli each week sparks hundreds of genetic changes, activating some genes that fight cancer and switching off others that fuel them. They split into two groups of 24 men with pre-cancerous lesions and had them eat four extra servings of either broccoli or peas each week for a year.

            The researchers then took tissue samples over the course of the study and found that men who ate broccoli showed hundreds of changes in genes known to play a role in fighting cancer. They believe the benefit would likely be the same in other cruciferous vegetables that contain a compound called isothiocyanate, including brussel sprouts, cauliflower, cabbage, rocket or arugula, watercress and horse radish. Broccoli, however, has a particularly powerful type of the compound called sulforaphane, which the researchers think gives the green vegetable an extra cancer-fighting kick. The broccoli eaters showed about 400 to 500 of the positive genetic changes with men carrying a gene called GSTM1 enjoying the most benefit. About half the population have this gene.   The researchers did not track the men long enough to see who got cancer but it is a very logical conclusion that  just a few more vegetable portions each week can make a big difference. Furthermore it is also likely that these vegetables work the same way in other parts of the body and probably protect people against a whole range of cancers.

The salicylate studies. In the UK , a prospective study was published in 2005, which evaluated dietary intervention, supplemented by oral sodium salicylate (an aspirin-like drug) and other anti-oxidants. A small cohort (group) of men with progressive early or relapsing prostate cancer had stabilisation of PSA, with a mean average stabilisation of 17.2 months. It was not clear which of the three components of the supplement were instrumental in this tumour stabilisation, or whether the combination was essential. Also, it was uncertain as to how much additional benefit was derived from the administered sodium salicylate or the natural salicylates found in the higher intake of fruit and vegetables. As a consequence, whether diet alone, salicylates alone or a combination of both is the optimal approach remained unanswered. For this reason our research group designed and conducted a double-blind, randomised, multi-centre controlled trial under the registration of the National Cancer Research Network (NCRN). It compared salicylates and lifestyle counselling versus Salicylates, lifestyle and mineral and vitamin c supplements in patients with progressive indolent or relapsing prostate cancer. The results confirmed the suspicions from other studies that giving a “one fits all” supplement to patients has very little benefit in terms of their cancer.  The result were fascinating, despite the fact that all patients were progressing a trial entry, 40% then stabilised for an average of 18 months. This trial was presented in the 2008 UK national research conference and gives reassurance that a change in lifestyle can slow the rate of prostate cancer progression although the exact role of salicylates needs confirming in further studies. Further analysis suggests that if patients were selected carefully the stabilisation rate is likely to be even higher.

The lycopene studies Following information gleamed from a large study of U.S. health professionals which showed that men with diets rich in lycopene (the red colour found in foods such as tomatoes), had a lower risk of prostate cancer, lycopene use was then investigated in men with established prostate cancer. Two small non-randomised studies showed that men with a high intake of natural lycopene intake in food, particularly tomato sauce, demonstrated a slowing of the rate of rise of the cancer marker, PSA.

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