Hotspots revealed by cancer atlas

Cancer death rates and types vary significantly in New Zealand from region to region, a new report shows.

The Health Ministry's Atlas of Cancer Mortality 1994-2000 reveals considerable variation in the death rates for 19 different cancers across the 21 district health boards.

It also highlights apparent cancer hotspots whose residents are significantly more likely than the rest of the country to die of five or more different types of cancer.

At the other end of the scale, people living in Wellington, Otago, Canterbury and Waitemata have significantly lower death rates for several cancer types, and higher rates for only one or fewer cancers.

With the exception of Counties-Manukau, the bigger centres seem to do better, raising the possibility the differences may relate at least in part to ease of access to treatment.

The report also reveals serious ethnic disparities - Maori are about three times as likely to die of lung, stomach and liver cancers as non-Maori, but are less likely to die from colorectal cancer.

Over the seven years covered by the report, more than 53,000 New Zealanders died of cancer, with lung, colorectal, breast, non-Hodgkin's lymphoma and prostate cancer the top five killers.

The report offers no explanation for the regional differences, but poverty, treatment quality and availability, access to doctors and ethnic makeup have all been raised as possible factors.

Barry Borman, manager of Public Health Intelligence - which compiled the report - said the trends had changed little since he wrote the last report more than 20 years ago.

The statistics were an indicator of a population's health, rather than a measure of how well the area's health service was doing, he said.

A higher death rate in one area did not mean a person had a higher likelihood of dying there than if they moved elsewhere.

Regional variation was inevitable, but in most cases it was hard to draw conclusions from the numbers, which did not take account of where the exposure occurred, Dr Borman said. Though a patient died in the Lakes DHB area, they may have developed cancer elsewhere.

In the case of lung cancer, however, there was a clear pattern of higher death rates in the central North Island, reflecting a higher population of Maori who were more likely to smoke, he said.

Otago cancer specialist David Perez said there were several possible reasons for Otago's lower death rates.

"Are Otago people presenting to GPs earlier - getting better access or can they afford to get in there earlier? Another wonder would be at the treatment end."

With a cancer centre under less pressure than its counterparts around the country, the hospital was able to pick up cancers needing further treatment and offer that treatment quickly, Dr Perez said.

Demographics could also play a part. Otago had a smaller than average ethnic population, but was not wealthier than the rest of the country, he said.

- NZPA

Regional trends

* Increased likelihood of cancer: Counties-Manukau and Taupo region
* Less likelihood of cancer: Wellington, Otago, Canterbury and Waitemata