Mrs Williamson's GP was urged to refer her to the clinic again if concerns persisted about her symptoms.
"No further action was taken by the GP, resulting in no further assessment by the [hospital]," Dr Brant said.
Mrs Williamson also had back pain, which became severe and prompted her to see a specialist in October 2007. Within days she was rushed to the hospital by ambulance because of the pain.
After an MRI scan, back x-ray and needle biopsy of her right breast lump, she was diagnosed with breast cancer that had spread to her bones. Eventually it spread to her brain.
She had chemotherapy, Herceptin and radiotherapy and, later, surgery. She continued to live a full life as a wife, mother, daughter, friend and businesswoman for almost all of her remaining two years until she died in September 2009.
"She wanted to do everything at 100 miles an hour," recalls Mr Williamson, 44, of Auckland.
She travelled to Tahiti on business, to Thailand with friends, and just hours before her death was planning a trip to Europe with her husband.
"The day she died she had been out having coffee and shopping with friends."
Dr Brant said she had an aggressive form of cancer which had probably spread by the time of the mammogram and ultrasound.
A review found "no obvious or overt malignancy or mass" visible on the mammogram or ultrasound that would prompt urgent review. Some cancers, including Mrs Williamson's type, did not show up on these scans.
The false negative rate when using the scans together was less than 10 per cent, and probably less than 5 per cent when clinical information was added, Dr Brant said.
Mr Williamson said his wife had received excellent care once diagnosed. But she had raised questions when the lump was first said to be "just tissue" and again later about the initial lack of a biopsy. She was fobbed off with medical reassurances.
"If someone is not completely happy with the answer that they get, don't just sit back and say, 'they said it's okay'. You know your own body better than anybody else."
