KEY POINTS:
A groundbreaking study linking occupation and cancer deaths in New Zealand women will be almost impossible to research further because of flaws in the way occupational data is collated, say cancer researchers.
A study of more than 7200 cancer deaths among women between 1988 and 1997 found occupational links to specific cancers. Nurses, for example, had a higher risk of dying from leukaemia, and teachers from breast cancer.
The study by Otago University's School of Medicine is the first analysis of cancer deaths by occupation among New Zealand women.
The results appear in the latest New Zealand Medical Journal.
But another study of this kind will be near impossible, said one of the researchers, associate professor of cancer epidemiology Brian Cox.
Statistics NZ stopped coding occupation from death certificates in 1999. The Cancer Registry has also stopped coding occupation from cancer patients in hospital.
While the information is still available, a lot of effort would be required to go back and group the occupation data.
Cancer Control Council chairwoman Dame Cath Tizard said cancer data collection should be as "robust" as possible. The council has been told that the Ministry of Health is undertaking a comprehensive cancer data project, which will be linked to improvements to the Cancer Registry.
WORKERS' RISKS
What the Otago study found:
* Clerical workers: Increased risk of non-Hodgkin's lymphoma and cancers of the breast, bladder, uterus, brain and rectum.
* Health professionals: Increased risk of leukaemia and colon cancer.
* Teachers: Increased risk of multiple myeloma and cancers of the breast, uterus and colon. Decreased risk of lung cancer.
* Farmers: Increased risk of cancer of the peritoneum (the membrane that lines the abdominal and pelvic cavities).
* Cleaners: Increased risk of cervical and ovarian cancers. Reduced risk of breast cancer.
* Textile workers: Increased risk of stomach cancers.
* Restaurant workers: Increased risk of thyroid cancer.
