← What's That Rash?
What's That Rash?
How to drive down your cancer risk
00:21:49
Lately there have been lots of scary headlines about cancer rates rising in younger adults. What can you do to drive down your cancer risk? Norman and Tegan offer some practical tips, and discuss what's in your control versus what isn't. References: Overview of cancer in Australia, 2025 - Australian Institute of Health and Welfare Effects of diets on risks of cancer and the mediating role of metabolites Be physically active – Cancer Council Exercise packs a punch in fending off cancer – the Health Report “You do not get cancer by chance”: Communicating the role of environmental causes in cancer diseases and the risk of a “guilt rhetoric” If you enjoyed this episode, check these out! How worried should you be about microplastics? Is your (artificial) sweet tooth killing you? What's so bad about fine particulate air pollution?
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- [00:01]
A
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- [01:01]
B
Listen, you know, there's one thing we haven't spoken about in the last few episodes. Do you?
- [01:08]
A
No. Now I'm trying to think of something flippant to say and I'm coming up empty. Norman, what haven't we spoken about recently?
- [01:13]
B
I don't think I've mentioned the Mediterranean diet for weeks.
- [01:18]
A
Do you know I have all of my musical instruments next to me today and I'm hoping I can have an excuse to use all of them and I think I might.
- [01:25]
B
Well, yeah, I'm not gonna talk about pleiotropy, but. What's pleiotropy?
- [01:30]
A
My xylophone. Wait, I'm going to bring my microphone close.
- [01:33]
B
And why there's more than one sign. There is that pleiotropy is the idea that one gene can have one effect on you, multiple effects, effects on your body. But that's getting far too technical because that's actually not what we're going to talk about. We might get to the Mediterranean diet on today's what's that rash?
- [01:50]
A
It's the show where we answer the health questions that everyone is asking.
- [01:57]
B
And this week our questions are about cancer risk, what we can do to drive down our cancer risk.
- [02:04]
A
Yes, exactly. So today's question comes from Alexandra. Norman has said before, writes Alexandra, that cancer rates are rising. But what can we do about this? On a personal level, how can we prevent cancer apart from diet, exercise and avoiding chemicals for women? Are things like preventive mastectomy regardless of genetics a good idea? Are there other things people can do? Would love to hear more on this. Well, Alexandra, you're in luck because we Are answering your question today. So I wanted to start with the idea of cancer rates and cancer going up. This is something that you have done so much reporting on recently. Norman, you had a Four Corners film that came out last year. What do we know about cancer rates?
- [02:46]
B
What we know is that overall, across all age, if you just average things out across all age groups, cancer rates are not rising. So in other words, your risk of having cancer per thousand of the population, according to your age, on average, overall, are actually going down. So cancer risk is actually falling. There are two things that are going up. One is numbers, because age is one of the strongest risk factors for cancer. And as there are more people who are older in the population, you're going to get more people developing cancer simply because it's a numbers game there. But your chances at 70 of having cancer are. Are lower than they were maybe two or three decades ago and seem to be continuing to fall, with one important caveat, which is the overweight and obesity epidemic, which does increase the risk. So some people believe that maybe that's tailing off. But overall rates are coming down, Numbers are going up. The other exception are young people. So young people, particularly in the 30s and 40s, what I showed in that Four Corners last year was that about 10 different tumors in young people are increasing. And it seems to be a generational phenomenon. With each generation, they seem to have a higher risk of cancer, which may well follow them through life. So they've been exposed to something earlier. Now, in absolute numbers, it's low. And you can get scary percentages, such as pancreatic cancer going up by 200%. But the actual numbers in young people are still low. But if that continues as these people get older, those numbers will not remain low. So young people rates are rising in some tumours, but the numbers are actually low. So the impact on the overall statistics is not huge, even though it's a major issue, particularly when it comes to colon cancer, which seems to be the main problem. But it occurs in other cancers too. So that's the kind of rate story. Sorry, it took me a while to explain all that. It is complicated.
- [04:45]
A
It is complicated. And I think the first part of what you said is worth sort of putting a little bit of a heavier point on is that we're successfully living longer than we used to. And because of that, we're living long enough to get cancer in some instances. We've also cut out a lot of the things that maybe in previous generations would have increased our cancer risk. So that older group is Getting less cancer, but there's just more of them in number.
- [05:08]
B
And the factor there is smoking.
- [05:09]
A
And so I suppose if you're in that older age group, you can sort of maybe breathe a little bit of a sigh of relief that statistically you're less likely to get cancer than you may have in previous generations. And so given that those guys are kind of like, okay, ish, let's focus on what we do know about, which is what you were just saying. Younger age groups may be a slightly increased risk of cancer. And talk about maybe some of the things that we can control when it comes to cancer risk with a giant asterisk that I'll get to later, because a lot of the things that seem like they could be under people's control often aren't.
- [05:44]
B
That's right. We can easily get to a blame situation where you develop cancer, but it's your fault because maybe your behavior has caused your cancer. And some people will get cancer no matter what. And some people will get cancer because of external variables such as air pollution or you're working in an occupation where you're exposed to carcinogenic chemicals. And it's not your fault. And sometimes you could have been exposed to something that's carcinogenic without you knowing it. So personal behavior can make a difference, but also what happens in the general environment makes a difference. But let's talk about what things that are under your control.
- [06:19]
A
Yeah. And so Alexandra's question, like, let's sort of go through them. You've already talked about smoking. That's a big one. We know that smoking is a big risk factor for lung cancer, breast cancer, stomach cancer.
- [06:29]
B
There's a whole list of cancers that are smoking related. It's not just lung cancer. Tobacco smoke is hugely potent when it comes to cancer causation and possibly other burnt plants as well. So it's quite likely that smoking cannabis is likely to cause cancer as well. And it looks as though from early evidence that vaping may well have a carcinogenic effect as well. So trading off tobacco for vapes might reduce the cancer risk a bit. But vaping is not a get out of jail in terms of cancer risk.
- [06:59]
A
The other big one in Australia is skin cancer.
- [07:01]
B
Yes. So sunlight is carcinogenic, and five or more sunburns during your life doubles your risk of getting melanoma. And even one blistering sunburn in childhood or adolescence more than doubles your chance of developing melanoma later in life. The nastiest form of skin cancer, the sun is evil.
- [07:18]
A
It wants to harm you, we're slipping, we're slopping, we're slapping, we're seeking shade, and we're sliding on some sunglasses.
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B
We are.
- [07:25]
A
Okay, so alcohol is another one that is actually a carcinogen.
- [07:29]
B
Yes. So there's a strong relationship between alcohol consumption and cancer. It's particularly so with breast cancer in women. It's there for bladder cancer with beer particularly, and it's there for colon cancer as well. So alcohol is a carcinogen. And as I say, the World Health Organization said there's no safe level. So the more alcohol you drink, the more you're at risk. And, of course, if you are obese and you've got fatty liver disease, the impact of alcohol on your liver multiplies. And that's not just for liver failure and cirrhosis. It's also for cancer of the liver.
- [08:10]
A
Okay, so you're taking all the fun things away from me, Norman, now, because the next thing on our list is ultra processed foods.
- [08:17]
B
Yeah. And it depends how you define that. But ultra processed foods may be related to early onset colon cancer, particularly in childhood, because it changes the bugs in your bowel and might actually introduce forms of E. Coli which produce toxins which are carcinogenic and then play out in that child's life so that they develop colon cancer in their 20s, 30s, or 40s. The other risk, which is well documented with ultra processed foods, is that they're cheap, empty calories. So they're high energy foods without much in the way of micronutrients or other benefits. And they are more likely to make you overweight or obese and contribute to that. Having excess levels of fat on your body, not subcutaneous, particularly visceral fat, does increase your risk of cancer because of the hormones that are produced by fat. And one of them in particular is something called insulin, like growth factor, which is recognized to be on the cancer causation pathway.
- [09:15]
A
Is the other part of it, beyond the excess fat and calories. Also that it's maybe displacing foods that might be protective, like fruits and vegetables that might have antioxidants in them that might be protecting yourself from cancer.
- [09:28]
B
Yeah. So we're being asked what you can do to protect yourself. And there seems little doubt that the Mediterranean diet has those factors that you're talking about is it's really hard to put on weight on the Mediterranean diet because there's so much unprocessed carbohydrate. And studies that have been done on the Mediterranean diet and trials where they really want to keep people's weight constant so that they just see the effect of the Mediterranean diet without its effect on weight, they will have to struggle to actually maintain the weight of people in the Mediterranean diet. But if you actually do that and you look at the Mediterranean diet itself, it has lots of factors in it that in theory are cancer protective, but they also help to prevent weight gain. And it may well turn out that in people who are on GLP1s that they may well have a cancer reducing effect over time. Probably it's too early to say because these are long term phenomena.
- [10:28]
A
How can you say that? What's giving us the indication that that might be the case if you say it's too early to say it's weight and fat loss?
- [10:34]
B
So if you're on a GLP1, this is not an ad for GLP1s, but if you exercise and you go on a mediterrane diet, your lean mass will go up less fat and therefore your cancer risk will go down. If that's what GLP1s do to you, then it's likely that they will have a similar effect. We will only measure that effect in the years to come because cancer causation is such a long process.
- [10:57]
A
All right, you said Mediterranean diet about 30 times. I'm just going to ring this bell a bunch of times just to get that out of the way. What about things that aren't the Mediterranean diet? Like there's the Mediterranean diet is not the only way to eat to be healthy. What do we know about other diets?
- [11:13]
B
Well, there's the mind diet, which is the diet that is designed to prevent or slow down the onset of dementia, which replaces some aspects of the Mediterranean diet with things like berries and maybe a bit more fermented foods such as yogurt. And there's the dash diet, which is a diet developed in the United States to prevent high blood pressure. It also seems to be cancer protective. And it's likely that other diets, such as for example the Vietnamese diet, which is actually quite similar to the Mediterranean diet in terms of its composition, may well have similar effects.
- [11:45]
A
So what we're talking about here is a diet that is low processed fruit and vegetable rich. Basically what we know. What we know. What we know is healthy and not much red meat.
- [11:55]
B
That's right.
- [11:55]
A
Okay, so we're talking about things that we can do to protect, actively protect ourselves. Now we've talked about diet. What about exercise?
- [12:01]
B
So exercise is definitely an anti cancer intervention. So if you exercise regularly, and it may well be that it doesn't take actually a Huge amount of exercise. But certainly if you are engaged in light, moderate, vigorous intensity exercise on a daily basis, you have a lower risk of cancer than individuals who are sedentary. The recommendation for the Cancer Council is up to one hour of moderate activity daily or 30 minutes of vigorous activity. So you've got to work a bit at it. There's various theories as to why this happens. It may well be that these growth factors which stimulate cancer growth are lowered and other benefits that we've yet to elucidate. It's likely that exercise improves the control of our genes, the sort of epigenetic control of our genes, rather than mutational activity, and settle things down. There's chemical messengers that come from your muscles called myokines, which influence other parts of the body. And the evidence is pretty strong with colon cancer prevention as well. And if you do develop cancer, your outcomes are better if you exercise. So good cancer centres now prescribe exercise as part of the treatment.
- [13:10]
A
I know that the question from Alexandra is specifically about cancer, and we're answering it thusly, but it does seem to me that with all of the things we've spoken about so far, cancer prevention is only one of the very, very many benefits that you get from these sorts of things, that only focusing on cancer maybe sort of misleads us on just how powerful these things are for our overall health, like exercise and eating. Well. It's not just about preventing canc, it's also about not getting frail in older age, staying strong, supporting your organ systems for all sorts of reasons, not just about preventing one category of illness.
- [13:45]
B
And it's likely that you can postulate what's going on here. But probably one of the potent things that's happening here is that those lifestyle interventions that we're talking about, diet and exercise in particular, slow down the aging process. And it's the aging process underlying all this that tends to increase the risk of coronary heart disease and cancer in particular. So you want to slow down the aging process. Naturally, you do it through exercise and diet and not making it worse with taking in carcinogens.
- [14:19]
A
Okay, so let's talk about some more medical interventions that we can do on the prevention side of things. Vaccination is a way to prevent certain cancers.
- [14:30]
B
It is. So the two vaccines, particularly that do that are the human papillomavirus vaccine in boys and girls. So it prevents cervical cancer in girls, but it also almost certainly prevents esophageal cancer and pharyngeal cancer in boys and anal cancer as well. So there's a Range of cancers that HPV vaccination prevents. And the hepatitis B vaccine is an anti cancer vaccine, particularly given in early childhood, given in the neonatal period, prevents cancer, particularly in children who may be in families where there's hepatitis B and resulting in liver cancer. So hepatitis B vaccine is an anti cancer vaccine as well.
- [15:12]
A
Okay, so I feel like we're giving Alexandra a lot of homework here. We're giving her a lot of different things that she can try. I want to talk about a few things that people, at least in the general public sometimes worry might be linked to cancer or that we've seen conflicting headlines around in the past. Plastics, what do we know?
- [15:31]
B
Well, I'll refer people back to our episode on microplastics and also I dealt with it in that four Corners last year on early onset cancer. There's no evidence that microplastics cause cancer. Doesn't mean to say they don't because in theory they could. They get into your bloodstream, they cause irritation and inflammation. So it's possible that microplastics cause cancer. We simply don't know. And what I've done is take the precautionary principle. If I don't need to have plastics, if I don't need to have non stick frying pans, I've slowly got rid of them. I've not rushed to get rid of them. I've slowly got rid of them and have not a plastic free house, but certainly a plastic reduced household. I have no idea whether that's going to benefit my health or not, but it's just taking that precaution. And then the other thing that we've talked about on whipstart rash before are artificial sweeteners. People believe that they cause cancer. And in our episode on artificial sweeteners, there's really no evidence of that.
- [16:25]
A
One of the things that Alexandra asked about in her question was preventive mastectomy, which is a pretty big step to take if you're worried about cancer. Is there any evidence for this if you don't have those very, very high risk genes?
- [16:39]
B
No. Part of the problem here is that when you do a mastectomy, you don't necessarily remove all the breast tissue. So it doesn't eliminate the risk of breast cancer, but it reduces it dramatically. Before you contemplate such a radical exercise, you, you need to talk it over your GP and you need to get genetic counseling. The argument for it is when you have a very strong family history, doesn't necessarily have to be the BRCA gene, but you can have a Strong family history, which suggests you are at very high risk. And you could consider having a mastectomy. And if you have the BRCA gene, then you need to consider having your ovaries out as well once you've had your children, because there's also a very high risk of ovarian cancer. You would not recommend mastectomy on a routine basis. For women who are at normal risk of breast cancer. You're five times more likely to die of coronary heart disease than you are of breast cancer and you're not going to take your heart out. So this is not something you would embark on without proper genetic counselling and good reason.
- [17:43]
A
The thing around the conversation about cancer, we talked a little bit about it before, that the sorts of lifestyle choices you can make that help prevent cancer have all sorts of benefits. But also just the wording of. Of modifiable risk factors or lifestyle factors sometimes implies that people have a lot more control over their lives than they actually do in real life. Something like fine particulate air pollution or being exposed to carcinogens in the workplace, if you're perhaps working with silica dust or that sort of thing. A lot of people don't have the agency to say, I don't want to live in this polluted city, or I don't want to work in this workplace, or you don't have a lot of say over the food that your parents give you when you're a child or the vaccinations that you have access to throughout your lifetime. That perhaps sometimes conversations like this. I worry that we end up putting so much emphasis on the individual that people then feel like it's their fault if something goes wrong, which is what
- [18:42]
B
government would actually quite like you to believe. Because it's their job to regulate occupational safety. It's their job to regulate environmental risks.
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A
And.
- [18:51]
B
And we've not done a very good job of regulating, particularly indoor air pollution, for example. We still have. We're not doing a good job of regulating fine particulate air pollution because that requires removing fossil fuels from the environment and we're not doing enough on that. So governments bear a lot of responsibility for the background cancer risk, which is out with our control, as do employers. And so there is a role for regulation in preventing cancer.
- [19:19]
A
And then alongside this is sort of the way that you maybe respond emotionally when, if you are the person that gets a cancer diagnosis or someone you love is where you kind of go, if only I hadn't done this or that. If only I'd taken these precautions when the truth is that all you're ever really doing is dialing up a risk or dialing down the risk. You could do all of the quote, unquote wrong things and dodge cancer your whole life. You could do all the right things and still get it. All you're really doing is increasing your odds or decreasing your odds at a population level, which is sort of disempowering as an individual.
- [19:55]
B
I agree. And you can only do what you can do.
- [19:59]
A
So, coming back to Alexandra's question, really, it was prompted by reporting that you've done Norman saying that cancer is on the rise in certain groups. What's our common sense advice to Alexandra and people like her who are worried about this?
- [20:13]
B
Stop worrying and start acting is really what I would say. It's not something to live your life in fear of. You know, some people do live their life in fear because they do carry a cancer gene and they know that they need to keep an eye on it. And some anxiety there is inevitable. But with a good general practitioner and good genetic counselling, you can really minimise your risk there. So don't live in fear of it, but do the sensible things. Don't smoke, don't drink alcohol to excess. Certainly don't believe that alcohol is helping you. Try and avoid polluting environments. Get some exercise and keep your weight down and you'll have done as well as you can.
- [20:52]
A
Well, thank you so much, Alexandra, for writing in to us. You can send us your questions. Our email address is thatrashbc.netau See you next week. See you then.
- [21:03]
B
Sam.