It is frequently deadly with risk factors largely unidentified, other than smoking.

The NSW Cancer Institute’s Incidence and Mortality Report 2007 reports that the mortality rate for the period 2003 to 2007 for the “largely hidden” cancer was higher in males in Greater Western,

when compared with the NSW average.

Released this week, the document also reveals that Greater Western residents, male and female, are on par with the men of the Hunter New England Area Health Service, as having “significantly higher” incident rates for lip cancer than the State average.

On the brighter side, Greater Western men and their mates in the Hunter New England Area Health Service were the least troubled by liver cancer, and Non-Hodgkin’s lymphoma was lower in female residents of the Greater Western.

The figures constitute vital information for the institute that has been charged with “reducing cancer incidence, increasing cancer survival, improving the quality of life for cancer patients and their carers and providing expert advice on cancer”.

Its senior epidemiologist Elizabeth Tracey yesterday told the Daily Liberal that unknown primary cancer was “a cancer that generally presents as metastatic disease and after investigation the primary cancer cannot be found”.

“Survival is generally poor, though it depends on the cell type,” she said.

“There is very little known about what the risk factors are, although smoking is considered to be a risk factor.”

Ms Tracey said a higher incidence in a particular region might indicate a higher proportion of people with risk factors.

“However, apart from smoking, little is known about risk factors,” she said.

“The difficulty with unknown primary cancer is that it may be because a person has presented late with metastatic disease or it may be because investigations fail to find a primary cancer.”

The institute reports that at 8

per cent of all cancer deaths in NSW, unknown primary cancer ranks equal third with prostate cancer, after cancers of the lung and bowel, as leading causes of cancer death.

The median survival for patients with unknown primary cancer

that has spread throughout the body is only three months,

compared to five months where the primary tumour is known, it says.