Before the surgery she had a mammogram, and was given the all clear.
"But about a month ago I was in the shower and I felt a lump - the only reason I felt it is because it was on top of the implant."
Because she'd had so much surgery on her breasts, her doctor said it was likely scar tissue or a cyst.
She insisted on a mammogram and, to avoid an eight-week wait, decided to go private. Luckily she had health insurance to cover 80 per cent of the cost.
That was three weeks ago.
"They knew instantly it was cancer as soon as they saw it on the mammogram," Adding told the Herald.
Doctors did an ultrasound, which as good as confirmed the diagnosis, she said.
"They did the biopsy then and there."
The following day, while sitting in her car outside Mitre 10, she was called by a medical intern at her GP's practice, and incorrectly told her cancer was grade two and growing faster than normal - when in fact it was grade one.
"It was just absolutely gut wrenching."
That evening, Adding had an appointment with a specialist.
Expecting her prognosis to be horrific, she was told she would need a mastectomy and possibly chemotherapy.
"I'm lucky, because the cancer I've got is slow growing," she said.
"It's not the real aggressive form that women seem to get in their 30s."
She said the main focus now was getting rid of it.
"I've got a boob on me that's trying to kill me. I just want it off."
If she'd gone through the public system, she'd still be waiting for a mammogram.
"If that was the case I wouldn't have found out I had cancer until the New Year."
She'll find out tomorrow when she'll have her mastectomy - likely no more than three weeks away.
"So hopefully by mid-November that breast will be gone."
She will lose her left breast and muscle from her back, which will be used for reconstruction.
The cancer has not spread, and Adding feels lucky. But coping has still been hard for her and her family - including her 10-year-old twins, and her two other daughters, aged 4 and 5.
"There are times when I feel really strong, and there are times when I just think it sucks - I don't want to have an operation, I don't want to lose a breast, I don't want to lose a back muscle.
"But I felt like I should go public, because I've got 43,000 women who are in that [age] catchment and if I didn't, I'd do them a disservice.
"I spoke to my husband before and he said maybe this was meant to be.
"Unfortunately I've got this, but lots of women do, but don't have the platform to get the word out to others."
She's reached quarter of a million others in just 12 hours and has been inundated with support and women sharing their own stories.
On Facebook, she urged evey woman to take action - regardless of their age or a family history of the disease.
"I'm not asking for sympathy or support, I have the most amazing network of friends and family around me.
"But I do ask you not to accept you're 'low risk', or to wait until you're 45 years old when you can get a free mammogram.
"Get a mammogram."
