A 40-year-old woman's breast cancer diagnosis was delayed more than six months after her doctor failed to make a referral.
The doctor - who can't be named for legal reasons - has been told to write a formal letter of apology to the woman after being found in breach of the Code of Health and Disability Services Consumers' Rights.
HDC commissioner Anthony Hill found the GP in breach of failing to include relevant clinical information in a woman's referral for a routine breast screening mammogram and failing to refer the woman for diagnostic testing.
The woman presented to her doctor in May 2015 with right breast nipple discharge but the doctor did not document this.
As the patient was overdue for her yearly mammogram, the doctor sent an e-referral to the District Health Board (DHB) Breast Service for a routine screening, without any clinical background.
The screen test showed no features suspicious for malignancy and nothing was followed up.
A few months later the woman saw a different doctor at the medical centre for a non-healing lesion on her right breast.
The GP advised the woman to have an ultrasound scan with a private provider but there was confusion between the GP and the woman as to who would organise the appointment.
Consequently, the woman did not get the scan.
In November 2015, when the woman took her son in for an appointment, she mentioned to another doctor that she had not heard back about the ultrasound scan appointment and was sent back to the Breast Service for further review.
The woman was diagnosed with breast cancer after finally undergoing the ultrasound and a biopsy in December.
Hill said the first GP did not provide services to the woman with reasonable care and skill and recommended the doctor write his patient a formal letter of apology.
"The GP failed to refer the woman for diagnostic testing, and her referral for the routine breast screening failed to provide the Breast Service with relevant clinical information that could have led to diagnostic testing, and earlier diagnosis of breast cancer," Hill said.
Hill also made adverse comment regarding the second GP's communication about the ultrasound booking, and failure to monitor timely completion of the ultrasound.
He reminded the GP of the importance of effective communication, including their responsibility to ensure that patients are provided with clear, preferably written, instructions for any investigations they are expected to organise themselves.