Despite chemotherapy treatment, McEwan died two years later. Her mother, Margaret Dynes says an early diagnosis could have saved her life.
"How could Susan have been failed, not once, but by 10 GPs over four years?" her mother asks. "There are no excuses.
"Also, there have been no repercussions. These GPs continue to practise with their dubious diagnostic skills."
She's now launched a petition calling on Prime Minister Bill English to create an oversight body, to independently monitor GPs.
"There are many more cases similar to Susan's and people need a Health Review Office, similar to the Education Review Office in education, which is taxpayer funded," she says on the online petition's page.
This would create "total reassurance" she said of an independent monitoring system with accountability for diagnostic failures, and failing to refer to a specialist.
"It is imperative that there must be more monitoring of general practitioners and accountability for their diagnoses and subsequent treatment," she said.
"It is unacceptable that patients like Susan - and there are many - have to suffer such negligence.
"Confidence must be returned to a visit to a GP."
Following McEwan's death, Dynes complained to the Health and Disability Commission, however her complaint was not upheld, according to the Southland Times.
It accepted doctors' advice that the diagnosis of ovarian cancer is difficult because of its vague symptoms, the Southland Times reports.
Dynes told the paper she was planning to present the petition to Clutha-Southland MP Todd Barclay, Act leader David Seymour and chairman of the health select committee Simon O'Connor.
Currently, doctors and other medical practitioners are overseen by the Medical Council, which registers doctors, and monitors standards, conduct and competence. However, complaints are referred to the Health and Disability Commission which then investigates.
Dynes told the Southland Times she wanted an organisation that checked on the performance of GPs as they worked, in a similar way to how the Education Review Office monitors schools.
Her petition has almost reached it target number of signatures.
Ovarian cancer symptoms - what to look out for:
The early symptoms of ovarian cancer are vague, or there may be no symptoms. However, symptoms can include:
• discomfort in the abdomen, or a bloated feeling, or pressure
• change in bowel habits, flatulence (wind), indigestion
• kidney or bladder problems
&bulll; abnormal vaginal bleeding
• occasionally, pain is the first sign
• the abdomen can become bigger due to a build up of fluid called ascites, which is caused by cancer
• women can lose weight despite having a bigger abdomen
(source: Cancer Society NZ)