Study shows boosting diet with supplements could halt prostate tumour growth and help men avoid unnecessary surgery, chemo or radiotherapy
Boosting the diets of prostate cancer patients could help them avoid going under the knife, experts have said.
Giving prostate cancer patients supplements that contain vegetables and “good” bacteria slowed progression of a crucial indicator of prostate cancer in the blood in an international trial. Now experts hope it could help prostate cancer patients manage the anxiety of knowing they are living with a slow growing tumour that may never harm them.
These patients undergo regular prostate-specific antigen (PSA) blood tests. PSA is a protein made by your prostate and raised levels can indicate tumour growth – but not always.
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The new trial led by Bedfordshire University gave men with slow-growing tumours a supplement containing broccoli, turmeric, pomegranate, green tea, ginger and cranberry. Half were also given a probiotic supplement containing the “good” bacteria lactobacillus.
PSA progression slowed significantly in both groups, but even more in the half taking the additional probiotic. The discovery opens the door to diet-boosting treatments, particularly for patients with slow-growing tumours which may not cause them a problem during their lifetime but are under active surveillance by the NHS.
First author Professor Robert Thomas, a consultant clinical oncologist, said: “Currently about 60% of men, with lower-risk disease, initially opt for active surveillance. But alarmingly over 50% opt out within five years.
As fewer than 5% of men in this prognostic group are likely to die from their disease, a successful dietary intervention, which helps men remain on active surveillance, could help avoid treatment-related toxicities in a large majority who might otherwise be over-treated.”
Many men on such a watch-and-wait course of action with the NHS struggle to deal with the uncertainty around PSA spikes during regular testing and opt to have their prostate surgically removed, or under chemotherapy, with life-changing consequences.
Evidence suggests PSA levels can rise for many reasons, including simple infections, and 75% of people with a raised PSA do not have prostate cancer. A raised level means men can be referred for unnecessary biopsies or MRI, or treated with surgery, chemotherapy or radiotherapy for tumours that may never cause harm.
Professor Thomas added: “What is particularly reassuring is that the changes we saw in PSA were supported by changes on MRI scans, which is very unusual and unique in nutritional research. This was a carefully designed clinical trial carried out under medical supervision and, while the results are encouraging, longer follow-up is planned to assess whether these supplements will lead to less men needing major interventions such as surgery or radiotherapy.”
Prostate cancer screening for most at-risk men was last year rejected by UK regulators. The UK National Screening Committee said the PSA test would lead to too much “overdiagnosis” if offered more widely.
Routine PSA testing is not currently offered on the NHS but you may be offered a test if a doctor thinks you have symptoms that could be prostate cancer. The rejection of widespread screening proved controversial as campaigners including Olympic cycling legend Sir Chris Hoy believe it should be offered to more men at greater risk, including those with a family history of the disease and Black men aged over 50.
Sir Chris has a terminal prostate cancer diagnosis after being diagnosed late despite having a family history of the disease. However the UK National Screening Committee stressed the “lifelong harms” from unnecessary surgery. They include urinary incontinence such as leakage when coughing, exercising or lifting, where incontinence pads may need to be worn”.
The committee decided that the PSA test is not accurate enough to justify inviting otherwise healthy men to be checked with it. Crucially, this decision was made because NHS data indicated that men struggle with a “watch and wait” approach and tend to insist they are treated.
After three years some 25% of prostate cancer patients initially placed on active surveillance have opted for treatment. After 10 years this is 50% and after 15 years has increased to 60%.
Professor Freddie Hamdy, a member of the screening committee, explained how this happens at a media briefing in central London last year. Prof Hamdy, of Oxford University, said: “I’ll give you the clinical scenario of the man who is on active surveillance. He’s fit and well but been diagnosed with prostate cancer. We do regular PSA tests, MRI scans and repeat biopsies.
“The slightest glitch in any of these, even if it is a PSA result which goes up only sporadically, the man is so sensitive to the possibility of disease progression that he will ask for treatment. And we find out after surgery, from testing, that the vast majority of these operations were unnecessary.”
