New Zealanders with cancer die from the disease sooner than Australian cancer patients, research shows, with some of the larger survival gaps in lung, liver and ovarian cancer.
If New Zealand's relative survival rate matched Australia's, 705 fewer New Zealanders would die from cancer each year, according to University of Auckland and Ministry of Health researchers.
The inequalities are detailed in a New Zealand Medical Journal paper, out today, comparing cancer survival rates in patients diagnosed from 2006 to 2010.
The bowel cancer survival gap, which puts New Zealand about 6 per cent behind Australia one year after diagnosis, has prompted a new call for a national bowel cancer screening programme.
For all cancers counted together, New Zealand's survival rate at five years after diagnosis was 4 per cent lower than Australia's.
At one year, New Zealanders' survival gap was more than 10 per cent lower for lung cancer, 14.7 per cent lower for female liver cancer, and 11.6 per cent lower for ovarian cancer.
For many cancers the gap had narrowed by five years after diagnosis, but for breast cancer it had widened to 2.8 per cent, from 0.7 per cent at one year.
Cancer epidemiologist Professor Mark Elwood and his colleagues say in the journal that Australia "shows very good overall cancer survival outcomes" on international comparisons.
Cancer survival has improved substantially in Australia and New Zealand.
Their findings suggest further improvements in recognition, diagnosis and treatment of cancer in New Zealand should be possible.
"As the survival differences are seen soon after diagnosis, issues of early management in primary care and time intervals to diagnosis and treatment may be particularly important."
Differences in cancer care are thought to underlie the transtasman survival gap, rather than differences in primary prevention, because earlier research has indicated the
two countries have comparable rates of people being diagnosed with cancer.
Professor Elwood told the Herald there was no doubt a national screening programme for bowel cancer would reduce the transtasman survival discrepancy in that disease.
"We've got excellent evidence that bowel cancer screening is effective at improving survival and reducing mortality."
The Government has said a national programme is inevitable but it will wait for the trial bowel screening programme in north and west Auckland to be completed and evaluated before making a decision. The evaluation report is due in 2016.
Professor Elwood said: "I'm not sure what they're waiting for."
The Beat Bowel Cancer Aotearoa lobbying and support group renewed its call for an immediate start on a national screening programme based on the new data.
"New Zealand lags well behind Australia in terms of detection, screening and treatment in bowel cancer," said chairwoman Mary Bradley.
"How many more Kiwis need to die before the Government acts ... ?"
Health Minister Jonathan Coleman said he had sought officials' advice on the "next steps for the bowel screening programme".
The Government needed to ensure there were sufficient bowel cancer health workers to deliver a high-quality programme.
He said the Government's new health target, that 85 per cent of patients referred with a high suspicion of cancer begin treatment within 62 days of referral, would help reduce delays.
Timeliness of treatment had already improved since the Government introduced a cancer waiting-time target in 2009.
Prompt diagnosis and treatment were more likely to ensure better outcomes for patients.
New Zealand's survival rates were above the OECD average for three "benchmark" cancers, of the breast, cervix and bowel, Dr Coleman said.
More than 21,000 newly diagnosed cases of cancer and 8891 cancer deaths were registered in 2011, the latest year reported publicly, although the official New Zealand Cancer Register includes the estimated 67,000 cases of non-melanoma skin cancer diagnosed each year.
5 ways to close the gap
• Increase public knowledge of cancer warning signs
• Bolster primary care and restore timely access to hospital specialists to reduce cancer diagnosis delays
• Start a national bowel cancer screening programme. Australia has one
• Spend more on high-tech medical equipment
• Study variations in cancer management more thoroughly
Sources: Professors Mark Elwood and Brian Cox, NZ Medical Journal