Everyday ways to prevent breast cancer

What does it take to prevent breast cancer? The answers are out there — if you can wade through all the research, that is. An estimated one in 9 women will develop breast cancer and one in 28 women will die from it. With statistics like these we want clear answers, not confusion.

But here’s another statistic: almost 40 per cent of breast cancer cases can be prevented through lifestyle changes. This estimate comes out of a new report from the American Institute for Cancer Research (AICR) and World Cancer Research Fund (WCRF). The study is an update to the breast cancer chapter in the 2007 report Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective. The initial project reviewed research from 873 studies about breast cancer prevention, including factors like diet, physical activity and weight. The new report factors in an additional 81 studies published in the last two years.

It’s a lot of research to wade through — that’s why there’s a panel of experts to make sense of it all. The goal of the project is to look at the data as the whole and pull out the proven strategies that people can use to reduce their risk.

Here are the panel’s recommendations:

Maintain a healthy weight. We’ve heard it many times before: being obese or overweight is a risk factor for many diseases. When it comes to breast cancer, extra weight (particularly around the middle) is a risk for post-menopausal women. Lean is better, provided it isn’t taken to the extreme of becoming underweight. (However, for pre-menopausal women, a little extra fat can be a good thing as it lowers risk.)

An excess of body fat affects the circulation of hormones, and makes ideal conditions for carcinogenesis. It can also stimulate the body’s inflammatory response (which in turn contributes to cancer progression).

Exercise. Physical activity is important at all ages, but even more so after menopause. Previous research has shown that working out helps the body’s immune system and reduces estrogen levels — a known risk factor for breast cancer.

We know the rules: at least 30 minutes per day, most days of the week. But do amount and intensity make a difference? Yes, according to the report. The risk of breast cancer decreases as the amount of exercise increases.

Furthermore, an October 2008 study by the U.S. National Cancer Institute found that regular vigorous exercise cut the risk of breast cancer in older women by 13 per cent overall. For women who were a healthy weight, that number jumped to 30 per cent. Similar effects were not seen with “light” activity.

Breastfeed exclusively for six months . It’s food for thought for new mothers, and good news for women who did it “the old-fashioned way”. Lactation reduces the risk of breast cancer at all ages. Breastfeeding is good for breast tissue because it reduces exposure to hormones and can actually help the breast shed cells with potential DNA damage.

Kids also reap the benefits. Other research shows that children who are breastfed for six months or longer are less likely to be obese or overweight in the future, which reduces their risk for a multitude of health problems.

Limit alcohol. When it comes to breast cancer increased intake means increased risk. However, since a moderate amount of alcohol can be good for the heart and the brain, experts are hesitant to tell women to cut it out completely. To stay on the safe side, the report recommends no more than one drink per day for women and two drinks per day for men.

These lifestyle changes can even help prevent a second breast cancer. A new study published in the Journal of Clinical Oncology found that women who were obese had a 50 per cent increase in their chances of developing a second breast cancer. Women who consumed one drink a day or more had a 90 per cent increase, and women who smoked had a whopping 120 per cent increase in risk.

The effect of hormones

Some factors we can’t control, but they can work in our favour. The report also found strong evidence that life events influence breast cancer risk. Starting menstruation at a later age (late menarche), bearing children (especially before the age of 30) and early menopause can have a protective effect.

The reverse is also true — early menarche, no pregnancies or late pregnancies and late menopause. Essentially, more menstrual cycles means more exposure to estrogen, and therefore greater risk.

What about hormone replacement therapy (HRT)? The report doesn’t go into a lot of detail, but does note that HRT is a cause of breast cancer — but the risk disappears within a few years after a woman stops taking it. Some birth control pills can cause a small increase in breast cancer risk, but this risk disappears after cessation.

General recommendations

In addition to these recommendations for preventing breast cancer, the WCRF and AICR also offer ways to prevent all kinds of cancer:

Eat well. Diet can make all the difference — particularly when it’s high-fibre, low-fat and includes plenty of vegetables, whole grains and legumes. Many foods that contribute to inflammation and weight gain are on the “limit consumption” list — namely red meats, processed meats, processed foods, salt, sugary drinks and energy-dense foods. (See Foods that prevent cancer for more details.)

Avoid tobacco. We often associate smoking with lung cancer, but it’s a risk factor for many other kinds of cancer as well, including those of the cervix, bladder, lip, kidney, esophagus, mouth, throat and pancreas. In short, don’t inhale it and don’t chew it.

Don’t worry about supplements. Anyone looking for a list of vitamins and foods to ward off cancer will be disappointed. Currently, the organizations don’t recommend using supplements to protect against cancer. There isn’t enough evidence to conclusively demonstrate whether certain supplements are helpful or harmful. More research is needed in these areas.

And what about toxins and chemicals in the environment? These factors weren’t included in this report, but scientists are still looking into these issues.

Of course, people who are a healthy weight, who eat well, exercise and don’t drink or smoke can still get cancer too. These habits can help prevent some cases, but there’s no sure-fire way to avoid cancer. These strategies are smart lifestyle choices in general, whether you’re looking to dodge cancer or a variety of other health issues.

Breast cancer facts*

– It’s the most common cancer among women. An estimated 27,000 women in Canada are diagnosed each year.

– More and more women are surviving breast cancer. While breast cancer still kills 5,400 Canadian women each year, death rates across all age groups have been declining since 1991. Currently, the 5-year survival rate is 87 per cent.

– Breast cancer affects men too. An estimated 180 men are diagnosed each year, and 50 will die from it.

* Statistics from the Canadian Cancer Society

ON THE WEB
Read the WCRF/AICR Second Expert Report online, or the press release.

Additional sources: CBC Health News, WebMD

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