At 34, Kirstin Pretorius was living her best life.

Married with two healthy and happy children, Kirstin's future looked bright, and she did everything within her power to ensure that it would remain that way.

From establishing fitness goals and maintaining a healthy diet to using chemical-free products to clean her home, health and wellbeing was one of Kirstin's biggest priorities.

Looking and feeling better than ever before, the 34-year-old was left reeling when doctors determined she had three cancerous tumours in her breast which were tragically making their way into her lymph nodes.

"In this picture, I was living with cancer. I just didn't know it yet. Ironically, this year marked the peak of my 'health' and my fitness," she wrote alongside a shot of herself and her husband celebrating their ten-year wedding anniversary.

 

In this picture, I was living with cancer. I just didn't know it yet. Ironically, this year marked the peak of my 'health' and my fitness. I've never felt better, stronger, or more comfortable with myself than I did turning 34. My marriage had never been better and my children were thriving. Everything was beautifully bright. But, despite feeling perfectly well, I went for my routine yearly health check. And that's when they discovered 'the limp'. The lump. I look at this picture from a simply blissful family holiday celebrating my 10 year wedding anniversary and all I can think is… 'KIRSTIN how can you not know that there are 3 tumours thriving away in your breast? How can you not FEEL the cancer slipping into your lymph nodes? Why don't you FEEL sick? How can you be so stupid?!' But I didn't know and I didn't feel. If my doctor hadn't examined me, I'd still be blissfully unaware, reaching new fitness goals with my body, eating my futile little anti-oxidant high virtually-vegan wonder food diet… I'd be packing my little plastic-free super food school lunches for my girls, lecturing them on healthy lifestyles. I'd be chemically-free cleaning my home wondering why the whole world doesn't use essential oils. All the while growing and feeding my precious cancer. So check your boobs. Know your body. Cancer happens. To anyone. #breastcancer #breastexam #cancersucks #knowyourbody

A post shared by Kirstin Pretorius (@kicking_the_big_c) on

 Determined to raise awareness of a potentially fatal disease, Kirstin has established an Instagram page dedicated to detailing her journey since being diagnosed with cancer in June of this year.

"I didn't know and I didn't feel. If my doctor hadn't examined me, I'd still be blissfully unaware, reaching new fitness goals with my body, eating my futile little anti-oxidant high virtually-vegan wonder food diet," she wrote.

Kicking_the_big_c is Kirstin's attempt to show 'the good, the bad and the ugly' side of cancer, and its treatment.

 
Using photographs to document the various stages of chemotherapy with her followers, Kirstin displays incredible strength of character, and has, unsurprisingly, been inundated with messages of support from people all over the world.

Ahead of her first chemotherapy session, Kirstin shaved her head, writing: "And it's done. I can't believe my dad flew across from the other end of the globe, to arrive just in time to get this shave behind us!"

"It's been a real challenge to try and feel comfortable and confident when my reflection doesn't look like ME," Kirstin wrote alongside another photo.

"I'm a bag of bones, pale and exhausted AND have no hair. But life carries on and I refuse to hibernate for 6 months," she told her followers.

"You're kicking it with such determination, class, dignity and awesome beauty," wrote one Instagram user following Kirstin's upload documenting her second round of treatment.

"You are going to kill cancer with your smile – what an inspiration- I wish you all the strength in the world to fight this battle," added another.

Kirstin's message is clear, and one which should be internalised by every woman; "Check your boobs. Know your body.  Cancer happens. To anyone."