sMater - Bowel Cancer | Dr Nadia Maqboul

Australia has one of the highest rates of bowel cancer in the world, with approximately 280 new diagnoses each week. 

This Bowel Cancer Awareness Month, Mater Private Hospital Redland gastroenterologist Dr Nadia Maqboul joins sMater to talk about the prevalence, latest research on risk factors, as well as the importance of the Bowel Cancer Screening Program. 

GP Education activity log:  

• Podcast title - sMater: Bowel Cancer Awareness
• Provider - Mater Misericordiae Ltd  
• Date published – 6 June 2025

Certificate of completion: https://www.mater.org.au/Mater/media/sMater-Certificates/sMater-Certificate-of-Participation-Bowel-Cancer-Awareness.pdf

To learn more about Mater, visit https://www.mater.org.au/

Transcript

Hello and welcome to this episode of SMater, a podcast by clinicians for clinicians

brought to you by Mater, an Australian leader in health care for more than a

century. My name is Jillian Whiting and I'm your host coming to you from 

Meanjin, the land on which this podcast is being recorded. And I'm Dr. Maria Boulton,

GP specialist and former president of AMA Queensland. Today we're joined by Dr.

Nadia Maqboul, interventional gastroenterologist at Mater Private Hospital Redland.

We are Mater. We are Mater. We are Mater. This is SMater.

Nadia, welcome to SMater. Thank you for having me, it's great to be here. This is

a topic that's really close to my heart because my father passed away from bowel

cancer and I don't wish that on anyone. Talk us through the prevalence of bowel

cancer in Australia and how that's changed through time. I think that's a really

important point. Sometimes looking at trends gives us a real good indication as to

how a disease is progressing and how some of our interventions may be making a

difference. When we talk about prevalence, what we're really looking at is the total

number of cases of a disease at any point in time.

on that, the incidence of colorectal cancer has been increasing over time. But again,

you'd expect that people are living longer as people get older, their risk of

colorectal cancer will increase with age. So that's not out of the ordinary. But

then if you adjust the data, so kind of control it for age and remove that

confounding factor of age, what you see is that the incidence rates have actually

decreased. And there's a good explanation for that. And that coincides with the

introduction of the bowel cancer screening program. So that kind of shows you that

there has been effectiveness of that. We'll talk a little bit more about that

screening program in a moment, but I wanted to ask about the risk of bowel cancer

with people with family history and without family history. Yeah, so the data has

really shown that having a family history does confer or can confer a higher risk.

And there's a few facts.

slightly higher than that of the average person. So you're looking at not quite

double the risk, so just under twice the risk, but the more family members, the

younger age of diagnosis, that risk can go up to anyway between four to 20 times

that of the average person. A common question we get asked by patients is what can

I do to reduce my risk of bowel cancer? What are the lifestyle modifications that

have been shown to work? I think this is really a great point at which we can

empower patients to take control of their health and make some simple modification

that can have quite long lasting impacts. So there's a few things that have been

shown across the day to have quite positive impacts. So if we look at dietary

factors, I think that's something that a lot of people would probably be aware of.

So consumption of red meat and processed meats is a big one. And that comes...

your diet, you should really limit the intake, minimize to no intake of processed

meats, that kind of cured meats, that kind of stuff. Why does red meat cause

problems? Well, there's various theories. I think the pathogenesis is thought to be

due to the heme content of red meat and the impact that has on the small bowel.

So red meat is predominantly the heme content of its processed in the small bowel

and that leads to a lot of kind of toxic chemical production.

your risk of developing colorectal cancer by at least 12 percent. So that's a really

important one. So fiber, have lots of fiber. The western diet has been implicated in

a negative way in terms of risk of colorectal cancer. So that's processed foods, is

that what you're talking about? Absolutely. So foods high in fat, sugars. And again,

the thinking behind that is that promotes obesity, which promotes cost synergenesis.

So again, I would say diets rich in fruit, vegetables. If you look at some

observational data from pescetarian diets, you'll see that individuals who are on a

predominantly pescetarian diet have about a third less risk of colorectal cancer. So

there are trends there that we're seeing. A couple of modifiable other risk factors,

I think we should touch upon smoking, clearly linked to colorectal.

compared to non -smokers. And then the other one is alcohol intake. We know that

alcohol does contribute to increased risk. It's difficult to say to what degree.

I mean, the current Australian guidelines are that you shouldn't have more than 10

standard drinks per week and no more than four standard drinks in any one setting.

But if you look at the WHO guidance, we now know that alcohol is quite cosynogenic

and we don't know the threshold at which that cosynogenesis pathway is activated.

So actually there's no real safe limit of alcohol but I think in terms of patients

we should be encouraging them to decrease their alcohol intake as much as possible.

That'll make sense, less red meat, more fiber, stop smoking and limit alcohol intake

more fruit and vegetables. Nadia, what's the current evidence on the use of aspirin

or other medications for bowel cancer prevention? Yeah, this is a great question and

I think I've been asked this quite a few times. A lot of the data does come from

aspirin. Other agents have been studied, so cholesterol lowering drugs like statins

metformin, which is a drug used in type 2 diabetes, but the evidence for those

isn't consistent. So I suppose the most consistent data is from aspirin. If you look

at the data, a lot of the evidence comes from cardiovascular studies. We use aspirin

for cardiovascular disease. So the primary endpoint in those studies that was being

looked at was cardiovascular endpoints. Incidents of colorectal cancer was very much a

secondary endpoint. If you delve a bit deeper, a lot of the patients recruited into

those studies were older. So kind of 50 plus.

there for screening colonoscopy and then other high -risk people with family history

again individualized have the discussion way up the pros and cons. When do you refer

people for genetic screening? I mean you mentioned some genetic syndromes but I'm

really keen to know we had a patient who had multiple polyps. I mean would you

refer, when do you refer their family for screening? Yeah it's a tricky one because

there are a variety of polyposis.

a Lynch syndrome or you know other genetic predispositions and in those situations

we're very much guided by the report we get from the pathologist. So it's a bit of

a multidisciplinary approach and very much dependent on the index case and what the

histology shows on that index case. We do now have quite clear guidelines for some

of the polyposis syndromes and if you know that a family has there's Lynch syndrome

within that family, then you usually would start screening individuals from the age

of around 25. According to the Australian Institute of Health and Welfare,

approximately 6 million people were invited to participate in the National Bowel

Cancer Screening Program between January 2021 and December 2022. Of those,

40 per cent participated in the program, the re -participation rate of Those who took

part in their previous invitation round and received the subsequent screening

invitation was 81 .1%. If we come back to the National Bowel Cancer Screening

Program, there's been some recent changes with the age eligibility. Can we say at

this point how that has impacted detection rates? This is an area that I'm

particularly interested in. We're seeing this global phenomenon of increased color.

overlap with those that we see in older age groups. But there's some kind of more

newer theories emerging, but in terms of screening, I think it's a little bit early

to say, but we can extrapolate from data from the older age groups. We've seen

improvements, we've seen improved mortality, extended kind of five year survival rates.

So I think that will come, and I think it will be born out over time. We see

some patients not participate in screening programs and perhaps bowel cancer screening

suffers from the fact that it's not as sexy, really it isn't. And I just wonder

what strategies we can use to encourage more patients to participate in screening

program for bowel cancer. There's some really interesting data around this and I

think GP specialists play a pivotal integral role in this. There's data that shows

that GP specialists talking to patients and encouraging them to have screening means

increased uptake of screening. So I think that that's the key. That's where we

should be really focusing. Provision of test kits in surgeries also increases uptake

rather than relying on patients to kind of, often I I hear so many stories,

patients get the screening tests sent out and put it in a draw and it's forgotten

about. So I think GP specialists play a pivotal role and that's where the focus

should be. Is there an element of fear or misunderstanding and what can be done to

counter those things? Absolutely. The stool test is a non -invasive,

very cost -effective, safe test to do. But people do have preconceived...

some barriers when it comes to marginalised communities. How can we increase their

screening? Yeah, so the important thing here is if you look at the data and in

Australia specifically, it's around Indigenous populations. Their likelihood of being

diagnosed with colorectal cancer is exactly the same as, or their risk rather,

is exactly the same as non -Indigenous populations. However, uptake of screening is

half. So if you look at uptake in screening across the general population.

2018 in Australia to see how we can address some of these barriers and try and

overcome them and improve uptake and screening and some of the things that came out

was culturally appropriate methods of relaying information.

People having trust in the healthcare provider, giving them the information. mobile

screening units particularly in remote and regional areas and then following up non

-responders why haven't people engaged? I think sometimes people don't engage you know

we don't address that aspect of what the reasons could be so they were the key

things that came out from that study. If you then extrapolate even further and look

at UK data there's a big Southeast Asian population. And again,

same pattern. Their uptake in screening is about 50 % of that of the Caucasian

population. So they also, the National Institute for Clinical Excellence had a look

at that. How can we improve this? Where can we intervene? And some of the factors

that came out was the taboo of a cancer diagnosis, the stigma. Talking about cancer

is not something that's done within families. literacy was an important factor, often

the elders rely on younger people for that kind of information. So again,

engaging with communities, engaging with faith leaders was seen to be a positive step

towards improving screening. In your view, what are the benefits and limitations of

fecal or cold blood testing as a screening tool? So It's probably the most widely

studied as a population screening tool and it's the most cost effective and it's the

most acceptable. Studies have shown that patients are more likely, despite what we've

discussed to do that, then go for a colonoscopy. It's non -invasive, it comes without

the risk of an invasive procedure. Colonoscopy is relatively straightforward, but

there's the requirement for bowel preparation, there's a requirement for sedation and

there are complications that can occur. There's been no kind of high yield studies

looking at colonoscopy as a primary screening tool and it's just not cost effective.

And I think if you look at it at an organisational level there will be other

factors. It's unlikely that that will ever be rolled out as a primary screening

tool, workforce issues, cost effectiveness, it's a costly procedure. So I think

they're the kind of barriers but overall the sensitivity of the FOBT is about 80 to

90%. It's a great test. Yes, it's not perfect but no screening test is but it's a

great test for screening at a population level in asymptomatic individuals. What are

the symptoms, Nadia, that you believe should prompt an immediate referral to a

gastroenterologist. There are certain symptoms as doctors that we call the red flag

symptoms and I think you have to interpret those in a bit more detail,

so acuity and severity of symptoms. One that always causes doctor's concern is for

example rectal bleeding. But then if you compare two individuals, someone who's had

bleeding for many years and many more, doesn't cause the same alarm, for example,

as somebody who develops sudden onset bleeding that's quite significant and occurring

regularly. So there's kind of a bit of risk stratification that you do as a doctor

when you're assessing patients. Again, there were some studies to look at various

factors and all their symptoms that are more likely to correlate with a concerning

diagnosis and therefore kind of assist you.

refer to a gastroenterologist. But I always say with the younger populations, they

behave a bit differently. So early onset cases, there is this age bias that we're

seeing. There's data that they will have multiple, often multiple visits to a health

provider before they are referred for a procedure. So I think always be aware of

the patient that keeps coming back with the same symptoms, especially if they're

younger. So they're probably the key points I would raise in regards to that.

The National Bowel Cancer Screening Program Monitoring Report 2024 noted that of the

64 ,932 participants with a positive screening test in 2022,

55 ,797 had a follow -up diagnostic assessment in the form of the colonoscopy.

Diagnostic assessment rates were higher for females than males and were slightly lower

for people aged 70 to 74 than for those in the 50 to 69 years age bracket.

Nadia, what happens when someone has a colonoscopy and they have a diagnosis of

bowel cancer? What happens next? I think that's a life -changing moment for the

patient. I mean, I look at it that they come in for a procedure and in that

moment you've really changed a lot of things for them. We're in a very privileged

position as doctors and I think dealing with that situation with sensitivity and

making sure that all questions are answered, obviously they will need ongoing

referrals for management and patients often have a lot of questions usually around

how bad is it? What does this mean?

cancer. You've got to give them time to process that. I think it's important to get

a family member with them for support. And then, as I said, make yourself available

so that if they have any questions after they've gone home, they have the

opportunity to address those and ask those questions of you.

And does your team organise all those referrals straight after and then link the GP

back in? Absolutely. We would take care of that. So I usually phone the colorectal

surgeon immediately after the procedure. It's a very anxiety inducing time.

You've completely turned their life around, really. And I think as much as you can

do to alleviate some of that concern, you're not going to get rid of it completely.

But it's about helping the patient through this process and making it as

straightforward as possible. So I usually ring straight away. We've actually had a

couple of cases where we've had early onset colorectal cancer and the turnaround time

has been amazing from diagnosis to surgery and cure because it's been early stage

has been a week. You know so people often barely have time for their feet to touch

the ground and it's all been sorted so I think that's a key component, we would

absolutely take care of that. The cases are usually discussed in an MDT setting

because there will be some situations where they require other treatments before

surgery and that's why we have all relevant specialists so that those discussions can

be held with all expertise present. It's extraordinary. So for those patients who've

been in that situation, they've had bowel cancer, they've had the cure, What do you

say about screening for recurrence after that, how often should they be screened? A

lot of that is based upon data that shows your highest risk of recurrence is in

that first 12 to 24 months after diagnosis. So provided they've had a complete

colonoscopy at the time of diagnosis, because there will be a small number of

patients who present acutely, say with a bowel blockage, having not had a full

colonoscopy may go to urgent surgery.

Those intervals may be adjusted if they have polyps in between and we would adjust

that according to the current guidelines. After that 11 year mark there's a couple

of ways you can approach it either they can do a stool test every couple of years

or they can have another colonoscopy at the 10 year mark. As GPs we recognise that

a diagnosis is a really busy time for patients and often they don't get to feel

those emotions have been diagnosed with cancer and they need a lot of support and

that's in the short term but I wonder about the long term what's our role as GPs

in monitoring these patients for the rest of their lives when it comes to bowel

cancer? Again I think GP specialists play the key pivotal role in that.

You've had relationships with your patients for many years and they're more likely to

confide in you to approach you about some of the issues that they may be having. I

think one of the most significant impacts can be those psychosocial issues that come

up. Often when you're in that mode of treatment, it's just like a treadmill, isn't

it? You're doing what you need to do to get through it. And then suddenly when all

that is done, that's when reality hits a little bit. So I think being alert to

those things and guiding them in regards to that. Sometimes there can be delayed

complications or issues that develop as a result of surgery or chemotherapy,

radiotherapy and I think again just recognising those and co -ordinating their care

and making sure they have access to their specialist because you play the key role

in that whole process. Given the changes to screening and increased focus on

prevention. What hope do you have for the future in terms of early diagnosis and of

course survivability as well? There's always hope and I think the evidence shows that

we already know the impact the bowel cancer screening program has had on mortality

rates, on five -year survival, on diagnoses. I think one key thing to point out here

is that whilst diagnosis of colorectal cancer

or over 70 % survival. So it's clearly been impacted and I have confidence that that

will be the case for this expansion of the age range and we'll see earlier

diagnoses, people getting treated, improvements in survival. Yep,

there's always hope. - You gotta do your screening though, right? - Absolutely, do the

screening. Don't put your screening test in a drawer and forget about it. The other

thing I will point out I would also encourage GP specialists to advise their younger

patients 45 to 49 year olds to opt in it's an opt -in system they won't be

automatically sent the test so please do that. Absolutely Nadia thanks so much for

joining us on SMater Today but before you go we'd like to introduce you to a

little segment we call the checkup.

So we're going to ask you five quick questions or Maria will ask you five quick

questions and it's aimed at giving our listeners and our viewers an insight into

you. Are you ready? I'll do my best. Nadia, what's your secret superpower?

I think my communication skills. I think I feel what patients go through.

Sometimes that can be a bad thing but I think it allows me to do my job as best

I can. - I'd agree with that, you've done fantastically today. And speaking of

patience, how do you want patients to see you? - I don't, you know, for me, it's

about we're all on the same level. I want you to be able to tell me your

concerns. I want us to be able to talk about stuff. That's the best way that I

can intervene and help you on your journey. So I think just feeling comfortable,

comfortable, open discussion, approachable. Who do you admire?

Who do I admire? I've been very fortunate to have some amazing supervisors throughout

my training. I've trained in London and I've trained throughout Australia. So I think

there's a few people there. I won't name names, but I've been very fortunate to

have been trained by some amazing people. They know who they are. I'll leave them

guessing. How would you describe your handwriting? Can I say I often get asked are

you really a doctor? I actually have quite legible handwriting unlike I'm gonna you

know bag out all my colleagues here but unlike some doctors my handwriting is quite

legible. What TV show best portrays your profession?

Not the medical TV dramas, there were none of them. A lot of people said,

you know, when I was at med school and junior doctor, Grey's Anatomy was like the

go -to.

It's not like Grey's Anatomy, there's not a disaster every single minute of every

single day.

That's a hard one, I don't know that there is one to be honest. Each day days

varied but it's fun, some days things are challenging but you know we deal with it

right. Nadia thanks again so much for joining us on SMater. No problem thanks for

having me. For our listeners at home or in the car or having a well -deserved break

between patients, thank you for tuning in. See you next time on SMater.