'Fit and healthy' mum diagnosed with bowel cancer shares signs everyone should look out for
A fitness coach previously diagnosed with bowel cancer has opened up about the warning signs she missed.
By her own admission, Danni Duncan said she’s the ‘freaking healthiest person’ she knows after doctors informed her of her stage two diagnosis in 2025.
The Melbourne mum-of-three hadn’t realised at the time what was developing alongside her growing baby.
Speaking to Kiddo for Bowel Cancer Awareness Month, Danni revealed: “During that pregnancy my iron was very low, so they sent me for an iron infusion. My levels increased at first, and everyone thought it was fine, but then my iron levels plummeted again.”
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Looking back, however, she realised that her toilet habits suggested that something wasn't quite right.
“About two years before I got diagnosed, I did start taking Metamucil every night before bed because I found I wasn’t going to the toilet regularly,” she explained.
“I would alternate between constipation and diarrhoea but I was diagnosed with IBS years ago, so I assumed that’s what it was. Irregular bowel movements were ‘normal’ for me but looking back I see that as a red flag.”
Having overlooked the signs, Danni carried on with her marathon training at 12 weeks postpartum.
Following spells of feeling dizzy and being unable to finish a set of weights at the gym, her husband Chris suggested that she should get herself checked.
A colonoscopy on 15 May 2025 revealed that she had a 2.7cm malignant tumour in her bowel.
Just two weeks later, she underwent a successful surgical procedure to remove 25cm of her bowel, along with three months of chemotherapy.
“I was told I wouldn’t be able to breastfeed my baby, and that was probably the hardest part. I breastfed London for the last time when she was nine months old," she said.
"The side effects from the chemo were atrocious. I suffered with extreme cold sensitivity and nausea but still tried to exercise throughout my treatment."
Later that year, Danni was able to complete a HYROX event with Chris, raising money for the Jodi Lee Foundation.
The race marks 12 months since Danni was cancer-free.
Surgeon's theory about why Danni developed bowel cancer
You might be confused how someone who runs marathons and continues to exercise through chemo could have developed cancer in the first place.
Danni said in a social media post: "The last four years I have eaten 80-90 percent whole foods, we use non-toxic products at home, I don't drink much alcohol, exercise every day and eat a high fibre diet."
She went on to say her doctor thought, however, that her habits as a child may have led to her cancer diagnosis in her thirties.
She said: "When I was in the surgeon's appointment on Monday, he said something so interesting.
"He said, 'This is what's happened - chemicals in your foods, carcinogens through red meat, burnt, barbecued, bacon, ham - they are environmental factors which we got exposed to in the 90s and we didn't know the long-term effects until now'."
According to Cancer Research UK, red meat is a group 2a carcinogen, which means it probably causes cancer. Processed meat, such as bacon, is a group 1 carcinogen, meaning it does cause cancer.
The NHS advises you do not eat more than 70g of red or processed meat a day on average, which is a little less than a quarter-pounder beefburger.
What is bowel cancer?
Bowel cancer, also known as colon cancer, is a cancer that's found anywhere in the large bowel, including the colon and rectum.
"How serious bowel cancer is depends on how big the cancer is, if the cancer has spread, and your general health," the NHS states.
Bowel Cancer UK reports that roughly 44,000 Brits are diagnosed with the disease every year, and the number of cases is increasing amongst adults between 20 and 50 years old.
What are the symptoms of bowel cancer?
According to the NHS, symptoms of bowel cancer may include:
· Changes in your pooing habits
· Bleeding from your bottom
· Feeling like you need to poo even if you've just been to the toilet
· Tummy pain
· A lump in your tummy
· Bloating
· Losing weight without trying
· Feeling very tired for no reason
If you are experiencing any of these symptoms, it is recommended that you book an appointment with your GP, where you'll be asked questions about your and your family's medical history, as well as undergoing a rectal examination.
You may also be referred to a specialist if the GP suspects there could be a possibility of cancer. Although, the NHS stress that these symptoms do not automatically mean you have bowel cancer.
If you’ve been affected by any of these issues and want to speak to someone in confidence, contact Macmillan’s Cancer Support Line on 0808 808 00 00, 8am–8pm seven days a week.
Topics: Australia, Cancer, Health, Bowel cancer
Anish Vij