Rachael Paxton is fighting fit. Having won countless triathlons locally and abroad, Rachael was at the top of her game, but as quickly as she reached her peak, her performance went into a descent for no apparent reason. That was until an unrelated health check led to a cancer diagnosis.

Fresh from a morning run, Rachael Paxton sits down opposite me and looks the picture of perfect health, but beneath the shiny exterior lies a sinister secret.

“The biggest misconception is unless you’re bald, you don’t have cancer,” she says.

Born in Roma and raised on a large cattle station, Rachael led an active childhood, riding horses and motorbikes and playing team sports including netball and basketball. But when Rachael ruptured her ACL (Anterior Cruciate Ligament) in her knee when she was nine years old, doing a handspring on her front lawn, she was forced to slow down – albeit just a little.

“It went ‘crack’ and felt like I’d broken my knee,” she says. “My dad is one of these hard country men and said, ‘Get up you’ll be right’. So I kept going and played basketball and netball for five years before I had it reconstructed.”

Harbouring a keen interest in sport and its effects on the human body, Rachael, went on to study Physiotherapy at the University of Queensland and in 2005 was offered the sole graduate position at Nambour General Hospital.

“I spent two-and-a-half years at the hospital and decided to move into a private clinic because I wanted to do sports and musculoskeletal work.”

But the biggest life changing moment happened at the end of 2006, when Rachael was in a RPM spin bike class.

The day I was diagnosed I’d swam 5km, had ran 10km and then went to the doctor at 9.30am.”

“The instructor said to me, 'You've got potential to ride a real bike and I've seen you run on a treadmill. You should try triathlons, you don't need to know how to swim!’ I had never considered doing triathlons before, I didn’t even really understand the order of it or anything.”

Keen to give it a go, Rachael ordered a bike and entered a race one week after it would arrive.

“I was living at Alex and came down to the car park at the library and rode around, practiced clipping in and out for 30 minutes and then I’d ride out to Fishermans Road and back – I was ready for my first sprint race tri.”

Rachael finished fourth in her category and a few months later completed her first Olympic distance triathlon.

Within a year Rachael was top of her age group at the Mooloolaba Triathlon, ranked second in her age group at the 2008 World Championships in Vancouver, won the 2009 Perth

Triathlon/Australian Age-group Championships, and came second overall at the 2009 World Championships on the Gold Coast. This all culminated in October 2009 with her professional international debut at the Putrajaya 70.3 in Malaysia, where she won her race.

In 2010 to 2011 Rachael competed in a string of international races with some impressive results, but within 18 months her performance declined for no apparent reason.

“I was never sick but had some hormone imbalances so was sent to see a specialist doctor,” she says. “With triathlon and the amount of training you do, it can really affect your female hormones. I hadn’t had a period for seven or eight years and my GP was very persuasive to see a specialist.”

The endocrinologist found a suspicious lump in her neck and within two weeks Rachael was diagnosed with papillary carcinoma – thyroid cancer.

“I was thinking, how can I have this when I’m not even sick and am still training? The day I was diagnosed I’d swam 5km, had ran 10km and then went to the doctor at 9.30am,” she says. “The day before my first major op I swam, worked and went for a run. I continued to do what I wanted because it helped me cope mentally.”

Following Rachael’s first operation in July 2013, she had radioactive iodine treatment – as thyroid cancer is slow-growing, chemotherapy is ineffective.

“The thyroid absorbs iodine,” she says, “it’s a one-off treatment where they give you a pill and shut you in an isolation room for three days, because your whole body is radioactive.”

In February 2014, Rachael had a recurrence and had one lymph node cut out, then another round of radioactive iodine, this time hit with six times the dose. But a review in August 2014 found the cancer had returned, prompting a third operation, but it didn’t work.

In December 2014, Rachael had what she thought would be her last operation, but four months later a biopsy behind her sternum showed more bad results.

“It’s a surgical cure so they’ll try and cut it out ahead of it spreading,” she says bravely.

Rachael is now facing the biggest surgery of her life, one which could stop her sporting career in its tracks.

“The surgery in my neck will potentially paralyse a vocal chord. That will mean half my airway will be permanently covered so normal breathing shouldn't be difficult but exercising to intensity will not be easy for me,” she says. “It’s horrible. The worst thing is not being able to finish on my terms.”

But before Rachael has to rack her bike, she’s aiming to complete an Ironman in 2016 – there’s no doubt it’s going to be a big year!