A young mum who was diagnosed with cancer after giving birth to her little girl has revealed her condition is now terminal.

Kellie Gardner,  27, the fiancée of Port Adelaide AFL star Jeremy Finlayson, first complained to doctors about her stomach cramps and severe nausea 17 months ago.

She was told it was likely a side-effect of her first pregnancy. 

After giving birth to her baby daughter, Sophia, Kellie hoped the painful symptoms would pass, but three months later they persisted and alarm bells were ringing louder than ever. 

Eventually a colonoscopy was performed and detected a tumour the size of a tennis ball that was blocking Kellie's entire colon. 

A year of intensive, gruelling treatment appeared to work, and Kellie believed her cancer had gone.

But in December, Kellie felt a tightening in her chest. At first, she thought it was Covid, but a PCR test was negative, Kellie revealed to the Soda Room podcast.

Doctors offered her CT scan, that revealed a mass the size of a tennis ball in her chest cavity, and later a bronchoscopy showed the cancer had metastasised and spread to her lungs.

- Change in bowel habits with diarrhoea, constipation or the feeling of incomplete emptying

- Thin or loose bowel movements

- Blood or mucous in stools

- Abdominal pain, bloating and cramping

- Anal or rectal pain

- Lump in the anus or rectum

- Unexplained weight loss

- Fatigue

- Unexplained anaemia

Source: Cancer Council Australia

On Tuesday, Kellie will begin a round of treatment for stage 4 cancer. 

'It was always stage four, but now it's terminal. Obviously, life expectancy can be longer, like they haven't given me a "like you've got six months to live make the most of it" sort of thing. But obviously it's spread to a new main function of your body, rather than just in the lymphnodes,' she explained.

'Now, it's all about controlling, managing that to a point that they can then do radiotherapy, possibly resect. I don't need all of my two lungs to survive. No, I won't run another marathon, but I don't need my whole lung. They can cut off a lobe, which is what I want so badly. But yeah, so it's just all about managing'.

The star added that she hopes to have another baby.

'So I’ve just actually this week had a fertility appointment, got my bloods taken … I would do it this year, if I could. Obviously, I can’t bring up a newborn right now,' she added.

Speaking about her initial diagnosis, she told Daily Mail Australia: 'I was in the worst pain of my life. I was constipated, had irregular bowel movements and awful pain in my abdomen'.

At the time Kellie, now 27, had just moved to Adelaide from Port Lincoln, while Jeremy had relocated after being traded from the GWS Giants to Port Adelaide.

They were juggling their 'new normal' lifestyle of being parents, and Kellie longed to spend time bonding with her baby.

'More than anything I just wanted to be there for Sophia but some days I couldn't. I missed a lot of special moments and memories because I was in and out of hospital,' she said.  

On December 6, 2021, Kellie spent her 26th birthday in hospital and started treatment soon after.

She stopped working, and her mum also left her job to help look after Sophia while Jeremy continued playing footy.

Kellie said she has 'never heard of cancer without death'. 

'I was at rock bottom. I was angry because I felt like it wasn't fair. My initial thoughts were that I would lose my hair from chemo, and that my partner would be a single dad if I didn't make it through,' she said.

'After the colonoscopy when I was told it was cancer I grabbed Sophia off the nurse and just wanted to hold her for as long as I could.'

Within two weeks of the prognosis Kellie had surgery to insert a colostomy bag to  divert food from her bowel. She then started chemotherapy and radiotherapy. 

'I was in denial for the first two to three months after and hadn't processed what was happening,' she said. 

Due to the severity of the cancer, doctors needed to start treatment urgently and there wasn't enough time to collect eggs for IVF. 

'We discussed fertility and IVF before I started treatment to collect eggs for a trial but it wasn't viable and would have delayed chemotherapy,' Kellie said. 

'If the cancer was in early stage three doctors would've been more lenient but it was already started to spread up my back.

'I remember Jeremy saying we can't take any chances and I need to start treatment rather than consider options to grow our family.' 

Over Christmas and into the near year Kellie started treatment, followed by chemotherapy in February 2022 for six months. 

By the end of it, Kellie was left infertile. 

'All of my plans to have a big family that I've had since I was a little girl have gone out the window,' she said.

Despite those dashed dreams, Kellie considers herself 'lucky' as the cancer reacted well to the treatment. 

'The hardest part of the entire process was knowing how much I was missing at home. It was absolutely devastating,' she said. 

'I feel like I was robbed of being a mum - Sophia took her first steps while I was in hospital, and even when I was home I wasn't really present, everything felt like a blur.' 

She then underwent a six-hour long operation to remove 25cm of her bowel and surrounding lymph nodes, which required spending 12 nights in hospital to recover, with the first night in intensive care. 

The surgery left her bedridden for four weeks and took 12 weeks to recover from. 

Due to her petite frame surgeons found her organs were 'fused' to her back, likely the result of radiotherapy, which lengthened the surgery time. 

On September 23, 2022 she had a final procedure to reverse her colostomy bag, and it took six weeks to 'learn' how to use her bowels normally again. 

'During that time I couldn't hold my daughter because my arms were so weak,' she said.

While her progress is encouraging, Kellie is yet to get the 'all-clear' and has a nervous wait before check-ups in January. 

All the treatment doctors had prescribed - from chemotherapy to surgery - 'did its job' yet she is understandably fearful the cancer will return. 

'I'm so anxious about it all - the easy part was being treated, now I need to try get back to life as normal,' she said. 

More than anything she hopes her experiences will make others more diligent about seeing a doctor if they are suffering pains, particularly as bowel cancer is occurring more frequently in young people. 

'It's not just an old person's disease,' Kellie said.  

'A lot of people also don't realise or know about the cost of medical expenses. Luckily I had health insurance and went through a private hospital. 

'We spent around $150,000, and only $50,000 was covered by Medicare. But you have no choice but to pay it when your life is on the line.'

If you'd like to donate to Kellie's GoFundMe page, click here.