A Dunedin woman is dying of cancer and her doctor's competence to practise will likely be reviewed.

For 27 days the doctor failed to follow up a scan showing an alarming 43mm mass - and then deleted the test results without following them up.

The woman believes her cancer could have been treated successfully had the scan been acted upon, and is urging people to follow up to get the results of all medical tests carried out on them to make sure nothing has been overlooked.

The Health and Disability Commissioner (HDC) has examined the case, and expert advice provided to him called the doctor's actions "a severe departure from expected standards of care, even if it was an unintended oversight.''

The test results were downloaded to the woman's file on March 17, 2016, but her doctor did not recall reading the ultrasound report until January 2017 - "I am unable to explain how this report was missed on my part; every doctor's nightmare,'' he told the HDC.

The woman's cancer remained untreated until she saw a locum doctor and the medical centre immediately sent her for an urgent gynaecological review.

That found she had advanced stage 4 endometrial cancer, which had spread to her bones, lymph nodes and lungs.

The woman told the Otago Daily Times the failure to follow up the scan results destroyed her family.

"Everyone is all just waiting for when it's going to end, and you don't know what's going to happen to who you leave behind.

"I do think I'm not the only one ... you don't know how to get out of it, and I am trapped in someone else's mess.''

Fear other patients might unwittingly be in the same position as her had led her to speak out, the woman said.

"If someone hasn't heard back, they need to be aware that sometimes the doctors don't always do their jobs properly and if you have been waiting on results you might need to jump up and down.''

The Health and Disability Commissioner also considered the role a registered nurse and the medical centre itself played in the handling of the woman's case.

The commissioner found the nurse's actions met accepted standards, but was critical the woman's symptoms did not prompt the nurse to further examine her clinical history - something which might have brought the missed test results to light.

He found the medical centre's record management system was adequate, but as the doctor was a partner and director of the centre, it was vicariously liable for the doctor's breach of standards.

The doctor was ordered to provide an audit of his clinic records to ensure abnormal results had been communicated and followed up appropriately, and apologise to the woman.

The commissioner also recommended the Medical Council review the doctor's competence.

The woman saw her doctor in June 2015 after a fall and mentioned she had been having erratic and heavy periods.

After a return visit in December, the doctor ordered blood tests, and after seeing those results referred the woman for an ultrasound.

That was performed in March 17, 2016, and the subsequent report - sent to the doctor the same day - identified a 43mm round mass and recommended urgent gynaecological referral.

Records showed the doctor removed the woman's ultrasound scan result from his in-tray on April 13, but he did not review the report at that time.

"I am critical that the report remained in Dr A's in-tray for 27 days, and that he then removed it without taking appropriate action,'' the HDC report said.

"It is deeply concerning that Dr A also marked Registered Nurse C's task message, which would have served as a reminder to follow up on the result, as 'done' without acting upon it.''

It was well established that doctors owed patients a duty of care in handling patient test results, and that the primary responsibility for following up abnormal results rested with the clinician who ordered the tests, the report said.

"In this case the ultrasound report contained explicit instructions to arrange further assessment, and Dr A failed to do so ... there were also several missed opportunities for Dr A to follow up on Ms B's ultrasound result.''

Those omissions led to a conclusion the doctor failed to provide services to the woman with reasonable care and skill, the report said.