D espite the fact that one in two people will get cancer, many of us are ill informed about what 5️⃣ we can do to prevent it. How do oncologists live their lives based on what they know? Doctors share the 5️⃣ secrets of living healthily and the risks worth taking – or not.

1. No fumar

"The only safe amount of 5️⃣ smoking is no smoking, given how addictive nicotine is," says oncologist Charles Swanton, who treats patients with lung cancer and 5️⃣ is the chief clinician for Cancer Research UK. Witnessing the pain of lung cancer patients is a potent reminder of 5️⃣ just how devastating the consequences of smoking can be, Swanton says. And, he adds: "Smoking doesn't just cause lung cancer, 5️⃣ 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, 5️⃣ bile duct cancers and liver cancers, says that roughly 70% of cases of liver cancer he sees are related to 5️⃣ obesity. "Alcohol does have an impact, but nowhere near the same level," he says. "With cancer, the big cause that 5️⃣ everyone tells you about is smoking. When you look at the statistics at the moment, about 13% of the UK 5️⃣ population are active smokers and that is probably going to go down to less than 10% in the next few 5️⃣ years. When you look at being obese and overweight, one in three of the population in England are overweight, and 5️⃣ a further one in three are obese. So obesity is a much bigger risk factor now."

Joe O'Sullivan, an oncologist and 5️⃣ professor of radiation oncology at Queen's University in Belfast, agrees. The biggest lifestyle factor for prostate cancer is weight, he 5️⃣ says. "Too much fat, too much meat, too many carbohydrates. Anything that gives you a bigger belly – more than 5️⃣ a 34-36in [86-91cm] waistline – increases the risk. The kind of diet that we associate with the western world, lots 5️⃣ of saturated fats and eating more calories than you need."

Mark Saunders, a consultant clinical oncologist at the Christie hospital in 5️⃣ Manchester, says: "There is an increasing number of what we call 'early onset cancers' – cancers in the under-50s. In 5️⃣ colorectal cancer, this is increasing markedly, and I think the big things are lack of exercise, the wrong diet, obesity 5️⃣ and a westernised lifestyle."

3. Reduce your meat intake

Saunders points to the fact that an estimated 13% of 5️⃣ bowel cancer cases are linked to eating too much processed or red meat. The doctors are cautious about their own 5️⃣ consumption: O'Sullivan doesn't eat red meat and Swanton has reduced his intake. Sivakumar says he follows a plant-based diet, although 5️⃣ "mainly for animal cruelty reasons, rather than cancer risk". He says that the reporting of nutritional data about cancer can 5️⃣ be very confusing, and references the work of the statistician David Spiegelhalter from the University of Cambridge, who has shown 5️⃣ that even if everyone ate an extra 50g of bacon every day, that would only increase the incidence of colon 5️⃣ cancer from 6% to 7%. "I think it is about having a healthy, balanced diet," says Sivakumar, "and occasionally having 5️⃣ a sweet treat or a steak."

4. Avoid ultra-processed foods

"Processed food could be a reason that more younger people 5️⃣ are getting cancer," says Sivakumar, "but we haven't really deciphered that. We do know that processed food in general contains 5️⃣ a lot of stuff that normal food products don't. Again, it's all about risk: what does it actually mean for 5️⃣ you? Which I don't think we've really got to the bottom of." Instead, he says, we should have the "mentality 5️⃣ that we need to be eating healthier food" and, he adds, we probably also need to eat a lot less.

" We 5️⃣ very rarely, if ever, buy processed food," says Saunders of his diet. "Most of the time we go to the 5️⃣ grocer to get veg, the local butcher to get meat, and we eat a lot of fish. I do eat 5️⃣ red meat; I occasionally have a Sunday roast. We probably have one or two takeaways a year and it's usually 5️⃣ a disappointment. I eat biscuits at work, but we don't have them in the house. I'm definitely not perfect, but 5️⃣ I do try to control myself so that I reduce my risk of cancer." Not enough fibre is a risk 5️⃣ factor for bowel cancer, for which the classic "five a day" mantra can help. "There is loads of fibre in 5️⃣ 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 5️⃣ such a saint really," he says. Swanton admits that he has the odd glass of wine, and Saunders drinks occasionally. 5️⃣ Sivakumar says there is evidence that smoking and obesity are far worse risk factors for cancer. "Don't drink to excess," 5️⃣ he says, "but enjoy your life."

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

Professor Pat 5️⃣ Price, a consultant oncologist who helped to launch the Catch Up With Cancer campaign to lobby for better access to 5️⃣ treatment, says: "Go to your GP if you've got a symptom of cancer – coughing up blood, peeing blood or 5️⃣ rectal bleeding, or a pain, or a lump or something like that, things that you know are not right." There 5️⃣ is a full list of signs and symptoms on the NHS website. Try not to be embarrassed. "A lot of 5️⃣ older men in particular in the UK and Ireland are shy about talking about their genitals or their urinary function," 5️⃣ says O'Sullivan. "Hopefully, the younger generations will be much more confident in talking about it."

Saunders says: "The big ones for 5️⃣ colorectal cancers are bleeding and a change in your bowel habit. Go to see your GP – it may well 5️⃣ be nothing if you are young. But if it keeps happening, you have got to go back again and don't 5️⃣ give up if there's a change. It may well not be cancer. It could be something simple like a pile. 5️⃣ But you've got to be aware of your symptoms and do something about it."

7. Keep up to date 5️⃣ with screenings

"I've tried to be good about being up to date with my screenings: cervical, breast and bowel screening – 5️⃣ I absolutely welcome all that," says Price. "Only about 65% of women invited for breast screening in England currently attend. 5️⃣ We've all got busy lives; the last thing we want to think about is our symptoms or a screening test 5️⃣ which might find something. But remember, the chances are that it is going to be absolutely fine. The NHS does 5️⃣ thousands of mammograms every day. There are a very small number that are actually positive (about nine in 1,000 tests). 5️⃣ If they find something, it will probably be tiny and really treatable and curable. In some countries, there are no 5️⃣ screening programmes. We are really lucky to have them, and we should just take the tests when invited."

8. 5️⃣ Get physical

Price discovered a love of running in her 50s: "Getting out there in the fresh air, in the scenery, 5️⃣ with nature is the best thing for you in the world." As you get older: "You are not thinking, 'I've 5️⃣ got to get fitter,' you are thinking, 'I've got to stay healthy.'" Price does an impressive six hours of exercise 5️⃣ a week. "I think it should be more," she says, doing strength and conditioning, dynamic pilates, high-intensity interval training, and 5️⃣ a long run at the weekend. "I find doing the London Marathon gives me a real sense of purpose each 5️⃣ year, because I know what I'm training for. Also, at my age, if you can't be fast, be long. I 5️⃣ think that sense of pushing yourself to the limit is quite a healthy thing to do. Fitness is great for 5️⃣ getting older, and for your bones, muscles and mental health. I'm a real advocate of women of a certain age 5️⃣ getting running."

9. Wear sunscreen

"I avoid going out in the sun," says Price. "I never used to much, but I am 5️⃣ very aware of the risk of skin malignancy. So I cover up and am not a sun worshipper." Swanton says 5️⃣ he always "wears sun cream and, being bald, a sun hat in the sun".

10. Manage stress

"Life is very 5️⃣ stressful and many of us are ill informed about what we can do to prevent cancer. Stress itself hasn't been 5️⃣ proved to cause cancer, but it can mean that you live in a way that increases your risk," says Price. 5️⃣ Stress can sometimes mean that you eat a lot, drink a lot, or don't exercise. Mindfulness is really good, and breathing 5️⃣ techniques. I know they sound a bit minimal, but they can work for many people." Of a direct link between 5️⃣ stress and cancer, Swanton adds: "One of the reasons we don't yet know the answer to this question is that 5️⃣ we lack good models to simulate human stress in the lab, to be able to understand and study it. But 5️⃣ knowing about the emerging evidence on how the central nervous system alters the immune environment and reciprocally, how immune cells 5️⃣ communicate with the central nervous system, it wouldn't surprise me at all if there was a functional link. Over the 5️⃣ next five to 10 years, we may start to see an emergence of data testing the relationship between stress and 5️⃣ cancer."

11. Look into genetic risk

"About 7% of prostate cancers are genetic," says O'Sullivan, "and you may have a 5️⃣ BRCA, a gene mutation that is associated with breast cancer and prostate cancer." These are rare – only 1 in 5️⃣ 400 people have them. O'Sullivan says if men have a relative who has died of prostate cancer at a young 5️⃣ age, it is important to have a prostate-specific antigen test, which is available on the NHS, every few years from 5️⃣ the age of 50. "The earlier you catch it, the easier it is to treat," he says. The risk of 5️⃣ a faulty BRCA1 or BRCA2 gene is much higher for breast and ovarian cancers, says Price. "Prophylactic mastectomy is recommended 5️⃣ when the risk gets very high and patients often choose this instead of regular surveillance," she says.

12. When 5️⃣ faced with a diagnosis, knowledge is power

"If you are diagnosed with cancer, we try to advise patients to really sit 5️⃣ with it and come to terms with it," says Price. "Because it's not great – no one wants to be 5️⃣ diagnosed with cancer. But find out as much information as you can. Often the hardest thing is telling other people, 5️⃣ because of their reaction: some people don't want to talk about it, or even don't want to go near you. 5️⃣ Being open and honest can help, and make a plan with your doctors. Often patients find fear of the unknown 5️⃣ is the biggest thing. So if you can ask all the questions and know what you're dealing with, that can 5️⃣ help. There is a huge amount of support out there. People will help you on your journey."

13. Don't 5️⃣ fear treatment

Some people might be worried about getting checked out for fear of treatment, but it is always improving, says 5️⃣ O'Sullivan, particularly radiotherapy. "If people have symptoms, they can sometimes be reluctant to go to their GP because of the 5️⃣ worry of how bad the treatment might be. A lot of people will have relatives who have had a tough 5️⃣ time having radiotherapy treatment. But the science has improved dramatically. If you think about what your smartphone looked like 10 5️⃣ years ago, and what it looks like now, it is similar to the type of technological developments in radiotherapy, to 5️⃣ the point now where the side-effects are much reduced. Many people continue normal life around the treatment. In some radiotherapy, 5️⃣ after five days people can be cured."

14. Talk about it

"Cancer affects one in two people in their lifetime," 5️⃣ says Price. "Everybody knows somebody who has been touched by cancer. Sometimes, we fear it too much and think if 5️⃣ we don't talk about it, it won't happen to us. We need to be much more open about it in 5️⃣ our society." It is important to know, she says: "While cancer can be very bad for some, it doesn't always 5️⃣ equal death. For a lot of people, cancer perhaps means difficult treatment, and as the Princess of Wales has said, 5️⃣ there are good days and bad days. And then maybe you're out of the woods, and that is cancer survivorship. 5️⃣ Then you can start looking at how does that play into making life better. Everyone's cancer journey is different and 5️⃣ can be really tough; for some it works out and for some, sadly, it does not. As cancer doctors we 5️⃣ want there to be as good an outcome as is possible for every patient."

15. Live life to the 5️⃣ full

"My work has had a twofold impact," says Sivakumar. "One impact is seeing liver cancer – there are sensible things 5️⃣ you can do to reduce cancer risk there. But you also have to remember that most cancers are not preventable: 5️⃣ broadly 40% of cancer is preventable and 60% isn't. The other two cancers I see probably aren't in the fully 5️⃣ preventable category. The thing it has really taught me is about work/life balance, spending time with your loved ones and 5️⃣ making sure you have time to see them. I am a very firm believer in that."