Exercise can cut the risk of men developing prostate cancer by up to 51 per cent, the largest study of its kind has found.
Scientists found exercise – which can include gardening or walking – has a ‘far larger’ protective effect than previously thought.
Bristol University researchers looked at how active 140,248 men were by looking at variations in their DNA – rather than relying on questionnaires.
But the analysis showed the effects of the genes were smaller, suggesting it activity was the reason for the cancer-preventing benefit.
The results were the most striking for exercise, even more so than other risk factors for the killer disease such as family history.
Exercise can cut the risk of men developing prostate cancer by up to 51 per cent, the largest study of its kind conducted by Bristol Medical School has found
Dr Sarah Lewis, lead author, said: ‘Most of these men in this study were aged over 50 and we can assume they were not all marathon runners.
‘Our findings suggest that the more active you are, the better. We would recommend that men are as physically active as they can be.
‘Our evidence suggests being active will be beneficial in terms of their prostate cancer risk.
‘But it doesn’t have to be vigorous activity or playing team sports, you just have to move about.
‘Being active could be things such as gardening, walking or other activities that you can build into your daily routine.’
HOW CAN EXERCISE PREVENT CANCER?
Keeping active can help with weight management, which would reduce the risk of 13 different types of cancer of which obesity is a risk factor.
Evidence indicates that physical activity may reduce the risks of several cancers through other mechanisms, independent of its effect on weight.
For example, being active can reduce levels of insulin, a hormone which can affect how cells multiply – cancer starts when cells divide too much and multiple out of control.
There is substantial evidence that higher levels of physical activity are linked to lower risks of several cancers, particularly colon, breast and endometrial cancer.
In breast cancer, activity can reduce levels of oestrogen. Oestrogen is thought to encourage cells in the breast to divide more often.
Exercise can also reduce inflammation, improve the immune system and the digestive system.
On the other hand, sedentary behaviour, such as prolonged periods of television viewing, sitting, and lying down, is a risk factor for developing chronic conditions which include cancer.
Nearly all studies investigating the link between physical activity and cancer risk are observational, in which individuals report on their physical activity and are followed for years for diagnoses of cancer.
Exercising while undergoing cancer treatment can help prevent decline in physical function and control cancer-related fatigue, Macmillan Cancer Support say.
In the UK, around one in six men will be diagnosed with prostate cancer during their lifetime.
The WCRF said this risk could drop to one in 12 for men who are the most physically active.
Dr Lewis added that she hopes the study, published in the International Journal of Epidemiology, will ‘encourage men to be more active’.
The academic team was funded by the World Cancer Research Fund (WCRF) and Cancer Research UK.
They analysed DNA to measure physical activity among 79,148 men with prostate cancer and 61,106 without.
They looked at variations in a person’s DNA sequence which relates to how active they are, rather than just relying on what they say about their lifestyles.
Men who were the most active had a 51 per cent reduced risk of prostate cancer, compared with those who were the least active.
Dr Lewis said that although the study looked at particular genes relating to exercise, the effect of the genes themselves on prostate cancer risk was small.
Studies have previously found similar results for colon and breast cancer.
Dr Anna Diaz Font, head of research funding at the WCRF, said: ‘Up till now, there has only been limited evidence of an effect of physical activity on prostate cancer.
‘This new study looked at the effect of 22 risk factors on prostate cancer, but the results for physical activity were the most striking.
‘This will pave the way for even more research, where similar methods could be applied to other lifestyle factors, to help identify ways men can reduce their risk of prostate cancer.’
Prostate cancer mostly affects men over the age of 50 and risk factors include having a family history of the disease.
Almost 48,000 men in the UK are diagnosed with prostate cancer each year and it kills almost 12,000 men annually.
An estimated 174,650 new cases of prostate cancer will be diagnosed in the US each year. About 31,620 men will die from the disease in 2019.
The American Cancer Society says one in 41 men will die of prostate cancer.
WHAT IS PROSTATE CANCER?
How many people does it kill?
Prostate cancer became a bigger killer than breast cancer for the first time, official statistics revealed last year.
More than 11,800 men a year – or one every 45 minutes – are now killed by the disease in Britain, compared with about 11,400 women dying of breast cancer.
It means prostate cancer is behind only lung and bowel in terms of how many people it kills in Britain. In the US, the disease kills 26,000 each year.
Despite this, it receives less than half the research funding of breast cancer – while treatments for the disease are trailing at least a decade behind.
How quickly does it develop?
Prostate cancer usually develops slowly, so there may be no signs someone has it for many years, according to the NHS.
If the cancer is at an early stage and not causing symptoms, a policy of ‘watchful waiting’ or ‘active surveillance’ may be adopted.
Some patients can be cured if the disease is treated in the early stages.
But if it diagnosed at a later stage, when it has spread, then it becomes terminal and treatment revolves around relieving symptoms.
Thousands of men are put off seeking a diagnosis because of the known side effects from treatment, including erectile dysfunction.
Tests and treatment
Tests for prostate cancer are haphazard, with accurate tools only just beginning to emerge.
There is no national prostate screening programme as for years the tests have been too inaccurate.
Doctors struggle to distinguish between aggressive and less serious tumours, making it hard to decide on treatment.
Men over 50 are eligible for a ‘PSA’ blood test which gives doctors a rough idea of whether a patient is at risk.
But it is unreliable. Patients who get a positive result are usually given a biopsy which is also not foolproof.
Scientists are unsure as to what causes prostate cancer, but age, obesity and a lack of exercise are known risks.
Anyone with any concerns can speak to Prostate Cancer UK’s specialist nurses on 0800 074 8383 or visit prostatecanceruk.org