The experts: oncologists on the simple, doable, everyday things they do to try to prevent cancer

Despite the fact that one in two people will get cancer, many of us are ill informed about what we can do to prevent it. How do oncologists live their lives based on what they know? Doctors share the secrets of living healthily and the risks worth taking – or not.

1. Don’t smoke

“The only safe amount of smoking is no smoking, given how addictive nicotine is,” says oncologist Charles Swanton, who treats patients with lung cancer and is the chief clinician for Cancer Research UK. Witnessing the pain of lung cancer patients is a potent reminder of just how devastating the consequences of smoking can be, Swanton says. And, he adds: “Smoking doesn’t just cause lung cancer, but also cardiovascular disease such as heart attacks, stroke and vascular dementia – in addition to 15 other cancer types.”

2. Try to maintain a healthy weight

Dr Shivan Sivakumar, an oncologist who treats patients in Birmingham with pancreatic cancers, bile duct cancers and liver cancers, says that roughly 70% of cases of liver cancer he sees are related to obesity. “Alcohol does have an impact, but nowhere near the same level,” he says. “With cancer, the big cause that everyone tells you about is smoking. When you look at the statistics at the moment, about 13% of the UK population are active smokers and that is probably going to go down to less than 10% in the next few years. When you look at being obese and overweight, one in three of the population in England are overweight, and a further one in three are obese. So obesity is a much bigger risk factor now.”

Joe O’Sullivan, an oncologist and professor of radiation oncology at Queen’s University in Belfast, agrees. The biggest lifestyle factor for prostate cancer is weight, he says. “Too much fat, too much meat, too many carbohydrates. Anything that gives you a bigger belly – more than a 34-36in [86-91cm] waistline – increases the risk. The kind of diet that we associate with the western world, lots of saturated fats and eating more calories than you need.”

Mark Saunders, a consultant clinical oncologist at the Christie hospital in Manchester, says: “There is an increasing number of what we call ‘early onset cancers’ – cancers in the under-50s. In colorectal cancer, this is increasing markedly, and I think the big things are lack of exercise, the wrong diet, obesity and a westernised lifestyle.”

3. Reduce your meat intake

Saunders points to the fact that an estimated 13% of bowel cancer cases are linked to eating too much processed or red meat. The doctors are cautious about their own consumption: O’Sullivan doesn’t eat red meat and Swanton has reduced his intake. Sivakumar says he follows a plant-based diet, although “mainly for animal cruelty reasons, rather than cancer risk”. He says that the reporting of nutritional data about cancer can be very confusing, and references the work of the statistician David Spiegelhalter from the University of Cambridge, who has shown that even if everyone ate an extra 50g of bacon every day, that would only increase the incidence of colon cancer from 6% to 7%. “I think it is about having a healthy, balanced diet,” says Sivakumar, “and occasionally having a sweet treat or a steak.”

4. Avoid ultra-processed foods

“Processed food could be a reason that more younger people are getting cancer,” says Sivakumar, “but we haven’t really deciphered that. We do know that processed food in general contains a lot of stuff that normal food products don’t. Again, it’s all about risk: what does it actually mean for you? Which I don’t think we’ve really got to the bottom of.” Instead, he says, we should have the “mentality that we need to be eating healthier food” and, he adds, we probably also need to eat a lot less.

“We very rarely, if ever, buy processed food,” says Saunders of his diet. “Most of the time we go to the grocer to get veg, the local butcher to get meat, and we eat a lot of fish. I do eat red meat; I occasionally have a Sunday roast. We probably have one or two takeaways a year and it’s usually a disappointment. I eat biscuits at work, but we don’t have them in the house. I’m definitely not perfect, but I do try to control myself so that I reduce my risk of cancer.” Not enough fibre is a risk factor for bowel cancer, for which the classic “five a day” mantra can help. “There is loads of fibre in fruit and vegetables,” says Saunders, adding that you should eat more vegetables than fruit.

5. Drink less alcohol

O’Sullivan has given up alcohol: “I’m such a saint really,” he says. Swanton admits that he has the odd glass of wine, and Saunders drinks occasionally. Sivakumar says there is evidence that smoking and obesity are far worse risk factors for cancer. “Don’t drink to excess,” he says, “but enjoy your life.”

6. If you notice anything you are worried about, see a doctor

Professor Pat Price, a consultant oncologist who helped to launch the Catch Up With Cancer campaign to lobby for better access to treatment, says: “Go to your GP if you’ve got a symptom of cancer – coughing up blood, peeing blood or rectal bleeding, or a pain, or a lump or something like that, things that you know are not right.” There is a full list of signs and symptoms on the NHS website. Try not to be embarrassed. “A lot of older men in particular in the UK and Ireland are shy about talking about their genitals or their urinary function,” says O’Sullivan. “Hopefully, the younger generations will be much more confident in talking about it.”

Saunders says: “The big ones for colorectal cancers are bleeding and a change in your bowel habit. Go to see your GP – it may well be nothing if you are young. But if it keeps happening, you have got to go back again and don’t give up if there’s a change. It may well not be cancer. It could be something simple like a pile. But you’ve got to be aware of your symptoms and do something about it.”

7. Keep up to date with screenings

“I’ve tried to be good about being up to date with my screenings: cervical, breast and bowel screening – I absolutely welcome all that,” says Price. “Only about 65% of women invited for breast screening in England currently attend. We’ve all got busy lives; the last thing we want to think about is our symptoms or a screening test which might find something. But remember, the chances are that it is going to be absolutely fine. The NHS does thousands of mammograms every day. There are a very small number that are actually positive (about nine in 1,000 tests). If they find something, it will probably be tiny and really treatable and curable. In some countries, there are no screening programmes. We are really lucky to have them, and we should just take the tests when invited.”

8. Get physical

Price discovered a love of running in her 50s: “Getting out there in the fresh air, in the scenery, with nature is the best thing for you in the world.” As you get older: “You are not thinking, ‘I’ve got to get fitter,’ you are thinking, ‘I’ve got to stay healthy.’” Price does an impressive six hours of exercise a week. “I think it should be more,” she says, doing strength and conditioning, dynamic pilates, high-intensity interval training, and a long run at the weekend. “I find doing the London Marathon gives me a real sense of purpose each year, because I know what I’m training for. Also, at my age, if you can’t be fast, be long. I think that sense of pushing yourself to the limit is quite a healthy thing to do. Fitness is great for getting older, and for your bones, muscles and mental health. I’m a real advocate of women of a certain age getting running.”

9. Wear sunscreen

“I avoid going out in the sun,” says Price. “I never used to much, but I am very aware of the risk of skin malignancy. So I cover up and am not a sun worshipper.” Swanton says he always “wears sun cream and, being bald, a sun hat in the sun”.

10. Manage stress

“Life is very stressful and many of us need to try to deal with stress better,” says Price. Stress itself hasn’t been proved to cause cancer, but it can mean that you live in a way that increases your risk, she says. “It sometimes means you eat a lot, drink a lot, or don’t exercise. Mindfulness is really good, and breathing techniques. I know they sound a bit minimal, but they can work for many people.” Of a direct link between stress and cancer, Swanton adds: “One of the reasons we don’t yet know the answer to this question is that we lack good models to simulate human stress in the lab, to be able to understand and study it. But knowing about the emerging evidence on how the central nervous system alters the immune environment and reciprocally, how immune cells communicate with the central nervous system, it wouldn’t surprise me at all if there was a functional link. Over the next five to 10 years, we may start to see an emergence of data testing the relationship between stress and cancer.”

11. Look into genetic risk

“About 7% of prostate cancers are genetic,” says O’Sullivan, “and you may have a BRCA, a gene mutation that is associated with breast cancer and prostate cancer.” These are rare – only 1 in 400 people have them. O’Sullivan says if men have a relative who has died of prostate cancer at a young age, it is important to have a prostate-specific antigen test, which is available on the NHS, every few years from the age of 50. “The earlier you catch it, the easier it is to treat,” he says. The risk of a faulty BRCA1 or BRCA2 gene is much higher for breast and ovarian cancers, says Price. “Prophylactic mastectomy is recommended when the risk gets very high and patients often choose this instead of regular surveillance,” she says.

12. When faced with a diagnosis, knowledge is power

“If you are diagnosed with cancer, we try to advise patients to really sit with it and come to terms with it,” says Price. “Because it’s not great – no one wants to be diagnosed with cancer. But find out as much information as you can. Often the hardest thing is telling other people, because of their reaction: some people don’t want to talk about it, or even don’t want to go near you. Being open and honest can help, and make a plan with your doctors. Often patients find fear of the unknown is the biggest thing. So if you can ask all the questions and know what you’re dealing with, that can help. There is a huge amount of support out there. People will help you on your journey.”

13. Don’t fear treatment

Some people might be worried about getting checked out for fear of treatment, but it is always improving, says O’Sullivan, particularly radiotherapy. “If people have symptoms, they can sometimes be reluctant to go to their GP because of the worry of how bad the treatment might be. A lot of people will have relatives who have had a tough time having radiotherapy treatment. But the science has improved dramatically. If you think about what your smartphone looked like 10 years ago, and what it looks like now, it is similar to the type of technological developments in radiotherapy, to the point now where the side-effects are much reduced. Many people continue normal life around the treatment. In some radiotherapy, after five days people can be cured.”

14. Talk about it

“Cancer affects one in two people in their lifetime,” says Price. “Everybody knows somebody who has been touched by cancer. Sometimes, we fear it too much and think if we don’t talk about it, it won’t happen to us. We need to be much more open about it in our society.” It is important to know, she says: “While cancer can be very bad for some, it doesn’t always equal death. For a lot of people, cancer perhaps means difficult treatment, and as the Princess of Wales has said, there are good days and bad days. And then maybe you’re out of the woods, and that is cancer survivorship. Then you can start looking at how does that play into making life better. Everyone’s cancer journey is different and can be really tough; for some it works out and for some, sadly, it does not. As cancer doctors we want there to be as good an outcome as is possible for every patient.”

15. Live life to the full

“My work has had a twofold impact,” says Sivakumar. “One impact is seeing liver cancer – there are sensible things you can do to reduce cancer risk there. But you also have to remember that most cancers are not preventable: broadly 40% of cancer is preventable and 60% isn’t. The other two cancers I see probably aren’t in the fully preventable category. The thing it has really taught me is about work/life balance, spending time with your loved ones and making sure you have time to see them. I am a very firm believer in that.”