Dr Liz O'Riordan (right) at an event for the breast cancer charity Future Dreams last month with Elizabeth Hurley (centre) and artist Sam Jacobs, a Future Dreams trustee. Photo / Getty Images
OPINION
Liz O’Riordan is a British retired breast surgeon who has had breast cancer three times. She works actively in breast cancer awareness and support.
The lifestyle choices that impact our risk of breast cancer are the ones we can control – here’s how.
As a breast surgeon who was diagnosed with breast cancer at just 40 years old, I feel strongly about raising awareness of how lifestyle factors reduce our risk of breast cancer.
If we increase education and community awareness to help women and men make sensible lifestyle choices, more than one in five global breast cancer deaths could be avoided. I was glad to see new research from The Lancet Breast Cancer Commission earlier this year highlighting the link between breastfeeding, alcohol and breast cancer.
The biggest risk factors for getting breast cancer are out of our control: being female and getting older. What we can control is alcohol consumption, breastfeeding (to an extent), exercise and how much we weigh. Here’s how.
When I think back to the unhealthy life I had as a medical student and junior doctor in the 1990s, it would be easy to blame my breast cancer on the large amount of alcohol I drank, or the 15 years spent without regular exercise.
I wouldn’t have listened to anyone who told me not to drink so much when I was in my 20s. Like many young adults, it was how I decompressed after a hard day on the wards. I drank to fit in. I drank to have fun. I drank to let my hair down. At that age, it’s easy to think that cancer is something that happens to other people.
I can’t change the past but I can share the facts about alcohol and breast cancer so you can make an informed decision about how much you drink in the future.
The report from The Lancet found that one in 10 breast cancer cases in the UK is due to alcohol. That’s more than 4000 cases a year. There are two ways that alcohol can cause breast cancer. Firstly, it’s broken down in the body to a chemical called acetaldehyde that can stop cells repairing DNA damage. It also increases the amount of oestrogen and insulin in our bodies, which can make your breast cells divide more frequently, increasing the likelihood of a cancer-causing mutation.
The more you drink, the greater your increase in risk. If you drink two units a day, your risk increases by 9%. If you drink six units a day, your risk increases by 60%.
But what does a 9% increase in risk mean? In your 40s, you have a 1.5% chance of getting breast cancer. If you drink two units a day, that increases to 1.7%. In your 50s, your risk increases from 2.3% to 2.5%. So the actual impact of alcohol is small, but if you don’t exercise and you’re overweight, these increases in risk all add up.
It doesn’t matter what you drink, or whether you binge at the weekends instead of having a glass of wine each night. It’s the total amount you have each week, and there is no safe limit. If you want to cut down, try swapping alternate drinks for something non-alcoholic, or drinking only three nights a week instead of five.
You may have spotted the widely quoted headline saying that one in 20 breast cancer cases could be avoided by breastfeeding. For me, this one hurts to read. I married in my late 30s and having chemotherapy at 40 made me infertile before I had planned to have a family. Does that make it my fault that I got breast cancer because I didn’t get pregnant in my 20s? Many mothers can’t breastfeed for a variety of reasons and many women choose not to have children, or can’t have them.
I can reassure you that the impact of breastfeeding is not as large as the report, or the headlines, make it seem.
We still don’t know exactly how breastfeeding reduces the risk of breast cancer. It could be related to the changes that happen in the breast when you stop producing milk, and it mainly reduces the risk of triple-negative breast cancer.
What you need to know is that, for every 12 months a woman breastfeeds a child, her lifetime risk of breast cancer drops by 4%. You might think that sounds like a lot, but it’s not. If you don’t have a strong family history of breast cancer, your lifetime risk is 17%. A 4% drop in that risk gives you a 16.3% chance of getting breast cancer in your lifetime. That’s a very small drop in risk and doesn’t take into account other factors such as alcohol and exercise, which I’ll come on to later.
The one-in-20 figure assumes that women in developed countries have six children and breastfeed each child for one to two years, whereas most women now have two to three children and breastfeed for three to six months. So please don’t beat yourself up if you haven’t breastfed your child for a year or more. This is a global recommendation to improve breastfeeding education and support.
Regardless of what you weigh, between 2% and 10% of all breast cancers in the UK are due to physical inactivity. Regular exercise can reduce your risk of getting the disease by up to 20%. We still don’t fully understand how exercise reduces the risk of breast cancer but we do know that regular exercise can reduce factors that stimulate cancer growth, such as inflammation and levels of oestrogen in your blood.
Although I’m a passionate promoter of the power of exercise to prevent breast cancer risk and reduce the risk of it coming back, I have a guilty secret. I avoided sport at school and rarely set foot in a gym as a doctor. It was only when I became a cycling widow that I learned to love riding a bike, and regular exercise has kept me sane throughout my three bouts of breast cancer.
We should all be exercising for at least 30 minutes, five days a week, with three aerobic sessions getting our heart rate up so we start to sweat and two resistance-based sessions at home, outside or in a gym to build bone and muscle strength.
The final risk factor I need to talk about is how much you weigh. It’s hard to talk about and even harder to hear, but the facts are there. Being overweight increases your risk of breast cancer because fat cells increase inflammation, as well as releasing extra growth factors and oestrogen into the bloodstream, all of which can stimulate cancer growth. The more fat cells you have, the greater the risk.
About 8-13% of breast cancer cases in the UK are due to obesity, and one in four women in the UK are obese. The risk of breast cancer is higher for post-menopausal women. And because your risk of getting breast cancer goes up as you get older (in your 50s it’s one in 43; in your 60s it’s one in 29 women), the impact of being overweight really starts to kick in.
There are many reasons why people are overweight or obese (the terms used in the report). I don’t want to fat-shame anyone and being able to afford to buy and cook fresh fruit and vegetables is a luxury and a privilege, especially when many people in the UK rely on foodbanks to feed their families. If you do want to reduce your risk of breast cancer by changing the way you eat, you should try to follow a plant-based diet with a rainbow of colour, limiting red meat to three times a week. There is no food you need to avoid altogether, and no magic diet or supplement that can stop you getting breast cancer.
An updated edition of The Complete Guide to Breast Cancer, by Liz O’Riordan and Professor Trisha Greenhalgh, is published in NZ on November 3 (Vermillion)
If you want to work out what your personal risk of getting breast cancer is, there are two online tools that Dr Liz O’Riordan recommends. The Ibis Risk Calculator looks at your family history of breast cancer, how many children you have and whether you’ve used HRT. iPrevent’s calendar factors in how much you smoke, drink, weigh and exercise.
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