A woman wasn't told for four years that she had cancer, by which time it was too late to save her, a report has found.

Health and Disability Commissioner Anthony Hill described the care that the Waikato District Health Board provided the woman as "seriously suboptimal".

He says the DHB held primary responsibility for "the pattern of errors" in the case, the main cause of which was "a systems failure".

He makes a series of recommendations and says the DHB should provide a written apology to the woman's family for the failings that had been identified.

In May 2009, the woman, then 46 and suffering abdominal pain, had her appendix removed in a public hospital.

A histology from the appendix showed she had a tumour.

A junior doctor acknowledged the pathology report, but it wasn't seen by the operating surgeon and no follow-up treatment was arranged.

In 2012, the woman complained of lower abdominal pain to her GP, who referred her to the hospital.

Over the next 14 months, as she deteriorated, she was seen by different clinicians.

There were suggestions that her symptoms could be explained by endometriosis, but cancer couldn't be excluded.

In month 13, an obstetrician-gynaecologist, Dr F, asked for a general review of the woman.

During the review, a registrar noted the missed 2009 result, but there was no evidence that this was referred to Dr F.

The woman was later seen by a general surgeon, Dr H, who reviewed her case and noted the 2009 finding.

Further tests showed the tumour had spread and it was only then that the woman she was informed of her prognosis.

However, her condition was such that she wasn't able to have surgery. She was referred to palliative care and died.

Source: AAP.