The doctor made referral for an ultrasound scan which went ahead three weeks later. The results came back normal and a practice nurse told the woman that the scan results were "fine" with no follow-up required.
About eight months later, and two days after she had given birth to her second child, the woman came back for a further review.
Her breast was rock hard and tender, and the GP prescribed antibiotics for possible mastitis (inflammation of the breast). However, the symptoms did not resolve and the GP sent an urgent request for an ultrasound scan, which confirmed a diagnosis of breast cancer.
The woman died three years later in 2019, the HDC report said. She leaves behind her two young children and grieving husband.
Former Commissioner Anthony Hill, who investigated a complaint made by the woman's family, said her treatment highlighted the importance of GPs thoroughly investigating red flag symptoms, including referring to specialists as required, to ensure that opportunities for early diagnosis and treatment of breast cancer are not missed.
He said that the omission was a missed opportunity to diagnose and treat the woman's cancer at an earlier stage.
"The inescapable fact is that [the GP] should have referred [the woman] to a breast surgeon after her scan regardless of the scan results, because of the unilateral blood-stained nipple discharge, yet she did not," Hill said.
"The failure to do so led to [the woman] being informed that her results were fine and that no scheduled follow-up was required, and placed the onus on [the woman] to follow-up if she had further concerns, which was inadequate advice in the circumstances."
In the report, the GP said: "I do take on board the feedback resulting from [Mrs A's] case, that important safety netting advice in the context of a reassuring test could be strengthened or emphasised more."
Following the investigation, Hill recommended that the GP's medical centre conduct an audit of 10 randomly selected patients with a coded diagnosis of a breast symptom in the past year to ensure that the care undertaken is consistent with current guidance.
The former commissioner also told the medical centre to provide evidence of the steps it had taken to ensure a more robust safety-netting and follow-up process for high-risk patients.
He also recommended that the GP apologise to the woman's husband.
