How to avoid breast cancer

More than 44,000 women are diagnosed with breast cancer every year. The numbers have increased by more than 12 per cent over the past decade – and by more than 80 per cent since 1971. On present trends, the total could reach 58,000 annually by 2024, according to Cancer Research UK, but some simple lifestyle changes could prevent one in 10 of these cases. At the start of Breast Cancer Awareness month, we suggest 10 ways to change your life.

1. Drink less

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It may be unpopular, but it works. Every alcoholic drink a woman consumes on a daily basis increases her risk of breast cancer by 6 per cent. Drinking has been rising, especially among young women, and researchers estimate it accounts for 2,000 cases out of the 40,000-plus diagnosed every year.

Cutting down on drinking could be a wise move for the 18 per cent of young women aged 16 to 24 who consume more than three drinks a day.

But going teetotal may be a step too far. Moderate drinking is good for the heart, especially in middle age, and this could outweigh the higher risk of cancer. The dull but true reality is that moderate drinking is best for all-round health.

2. Eat fruit

You can't go wrong with this – almost all dietary advice comes down to the single instruction to eat more fruit and veg. Diet is thought to be a key factor in one in four cancer deaths – and animal fat in the diet is the suspect ingredient in breast cancer. The Japanese, who eat a diet of fish, rice and vegetables that is extremely low in animal fat, also have low rates of breast cancer.

A high-fat diet increases the levels of the female hormone oestrogen in the blood, which encourages the growth of cancer cells. In populations with a high-fat diet, women tend to start their periods earlier and reach menopause later so they are exposed to high levels of oestrogen for longer, increasing their risk of breast cancer.

Studies into what effect eating fruit and vegetables has on breast cancer have produced mixed results. One study found that, when combined with taking exercise, the results were dramatic. Published in the Journal of Clinical Oncology last June, it showed that women who ate their five portions a day and walked briskly for at least 30 minutes halved their risk of breast cancer.

3. Walk

It is enjoyable, simple and requires no equipment. Walking is good for all aspects of physical and mental health – and cancer is no exception. Brisk walking (or other exercise) for 30 minutes a day, five times a week, is all that's needed. Currently only one in four women manages this. If all women did, Cancer Research UK estimates it would prevent 1,400 cases a year.

Three large studies in Italy and the US showed that inactivity caused 11 per cent of cases of breast cancer. Exercise works best before the menopause, but it is effective afterwards, too. It is thought to alter oestrogen metabolism, resulting in a weaker version being made.

4. Avoid HRT

Hormone replacement therapy is seen as the principal avoidable risk for breast cancer. At the height of its popularity, in 2002, an estimated two million women were taking HRT in the UK, and millions more worldwide. Tens of thousands of women will have developed breast cancer, ovarian cancer and endometrial cancer (of the lining of the womb) as a result. Overall, women currently taking HRT are 63 per cent more likely to develop these three cancers than those who are not. Earlier hopes that these risks would be counterbalanced by a reduction in heart disease have not been borne out. Gynaecologists recommend that women who wish to use it to ease the symptoms of the menopause do so for as short a time as possible.

5. Get screened

Women diagnosed with breast cancer at the earliest possible stage have a nine in 10 chance of a successful recovery. This is the rationale for screening – to detect a tumour by mammography when it is still too small to feel. Women aged 50 to 70 are invited for screening every three years – shortly to be extended to ages 47 to 73. It is estimated that the scheme saves 1,400 lives a years in England – one life for every 500 women screened.

However, there is a downside in the shape of false alarms. Screening picks up abnormalities in the breast that look like cancer but turn out not to be. Several thousand women each year suffer the anxiety and discomfort of being recalled for further tests and undergoing biopsies of the breast to check for cancer – before being given the all-clear. Screening is now more accurate, since two views of the breast are taken, reducing the chances of cancers being missed.

6. Give birth

Having children, especially before the age of 30, helps protect against breast cancer. It is down to those hormones, again. Over the last century, economic progress has led to delayed childbirth and smaller families as women with their own careers have sought to balance the demands of work and home. But researchers estimate that delaying childbearing increases the risk of breast cancer by 3 per cent for each year of delay.

7. Breast-feed

Breast-feeding protects against breast cancer, as well as being best for the baby. But smaller families and the rise in the number of working mothers has meant the time spent breast-feeding has reduced. Breast-feeding for six months reduces the risk, experts say. Yet many women never get that far. In England, 77 per cent of mothers start breast-feeding but more than a third switch to bottle-feeding in the first six weeks.

8. Lose weight

Obesity increases the risk of breast cancer – but only after the menopause. A large European study called Epic found postmenopausal women who were obese had a 31 per cent higher risk of breast cancer than women with a healthy weight. Reducing obesity could save 1,800 cases of breast cancer a year.

Obesity increases the risk of other cancers including those of the bowel, womb, kidney and oesophagus. Overall it is estimated that 5 per cent of cancers in women and 3 per cent in men are due to being obese or overweight. In the UK, 12,000 people might avoid getting cancer each year if they maintained a healthy body weight.

9. Get a stressful job (really)

A 2005 Danish study published in the British Medical Journal found high levels of daily stress reduced the risk of the disease by 40 per cent. The researchers suggest that stress may be beneficial by reducing levels of oestrogen. They draw a distinction between daily stress of the sort experienced by women in high-pressure jobs and stressful life events such as bereavement, which have previously been linked with an increase in cancer. Stress can have other damaging effects, too – on the heart, for example, and by increasing the risk of compensatory behaviour, such as drinking.

10. Live somewhere clean

It has long been claimed that exposure to pollutants used in the manufacture of products from plastics to cosmetics has an "endocrine disrupting" effect. The chemicals are said to mimic the action of oestrogen and have been blamed for feminised fish and frogs and declining sperm counts in men. A report from the World Wide Fund for Nature last year claimed their role in breast cancer had been neglected. It pointed out that less than half of new breast cancer cases can be explained by genetic and lifestyle factors and chemicals in the environment could be the missing link. Other studies have contradicted this suggestion and experts point out that compared with the natural levels of oestrogen in a woman's blood, the level of the chemicals is too small to have significant impact.

Still, moving to an unpolluted region is unlikely to do harm and could encourage tother beneficial changes, such as eating healthily, exercising more, and drinking less.