On the mend, Margaret thought the health scare was behind her until two years later when she went for another routine mammogram.
The half marathon runner and triathlete says she was left shocked by the second diagnosis.
"I was gobsmacked. Things like this don't happen to me," she says.
"It was getting worse and before I knew it I was dealing with a serious grade of cancer.
"I always thought I would get over this hurdle and it will be a thing of the past."
Doctors had to remove her breast and as one of few women who develop complications after surgery, Margaret ended up dealing with lymphodema.
Lymphodema results in painful swelling of the arms and hands.
"It really knocks you around. It's just something you don't think about," Margaret says.
"Lots of people end up with serious damage."
Making contact with the Rotorua Breast Cancer Trust, Margaret joined Pilates and took up an Encore programme of gentle exercises and relaxation techniques.
"They were so valuable. It helped me get back to some degree of normality.
"For a lot of people who have radiation or surgery it has a real impact on their body ... I had to really keep on top of the lymphodema with gentle exercises, movement and massage. Encore provides you with so much support," she says.
Margaret is now the assistant co-ordinator of the Rotorua Encore programme and she encourages women who have or have experienced breast cancer to take on the free therapeutic exercise programme.
"Programmes like Encore help women to take charge of their own health and recovery after cancer treatment.
"Once the doctors have done their bit to save our lives, it's up to us to regain our strength and live a fuller life than ever," she says.
Encore is an eight-week free programme to be run at the Polynesian Spa starting February 7.
It is a nationally-run programme by the YWCA and is conducted by women incorporating gentle exercises, relaxation techniques, information and support.
Women wanting to attend must enrol and medical consent is needed for the free programme.
Inquiries and registrations can be made by calling the Rotorua Cancer Society on (07) 349 4556 or toll free 0800 ENCORE (362 673).