Saliva swab could save lives from cancer

Nurses and other health professionals could be administering saliva swabs in healthcare settings to predict someone's risk of developing cancer in the near future.

University of Melbourne researcher Sibel Saya kicked off an Australian-first study earlier this month that could potentially curtail cancer-related deaths.

The saliva test, called a polygenic risk score, looks at a couple of hundred differences in our DNA associated with increased risk of the four most common cancers.

Annually, breast, bowel, prostate and melanoma account for 50 per cent of all cancers diagnosed in Australia.

Saya said that while we all carry some of these DNA variants, having more than average can indicate someone is at a higher risk of developing cancer.

"When you know you have an increased risk of a certain type of cancer, you can start screening earlier or more frequently and keep an eye on managing that risk," Saya said.

"Hopefully, if there's cancer to be detected, it can be picked up as early as possible."

Each year, close to 50,000 Australians pass away due to cancer, averaging 135 people each day.

Nurses play a pivotal role in cancer screening as they're often the first line of communication and keep close contact with the person seeking health advice.

The World Health Organisation emphasised that nurses are the ideal group to [train to] detect signs of cancer, to promote awareness, lead interventions and provide individualised care.

Saya said the study focuses on general practice settings where these DNA tests could be most accessible to all Australians.

"Practice nurses, being a key part of preventative healthcare in that setting, could potentially be discussing this type of risk test as part of routine health checks for patients," she said.

Currently, most genetic testing looks at mutations in genes that could indicate a high-risk hereditary link to developing some of the most common cancers.

For example, the genes BRCA1 and BRCA2 have been strongly linked with hereditary breast and ovarian cancer. 

However, this type of genetic testing is only done in people with very extensive family histories of cancer. 

Polygenic risk scores can be offered to anyone in the population to better inform them of their risk.

"Apart from those people with a substantial family history, we do not use genetic testing to predict someone's risk of cancer at the moment," Saya explained.

"For everyone else, we use age and family history to gauge their cancer risk.

"So, it's a pretty blunt way of determining risk factors."

Saya found in her PhD study in 2020 that 84 per cent of her participants were interested in doing the DNA test and learning the results.

She said it showed that people wanting to be screened were accepting of a DNA risk test.

"It could make testing more accessible for everyone at a lower cost."

It's estimated the federal government spends around $4bn each year on cancer research, programs and screening.

Annually, nearly $6bn of the total Australian health system's costs goes to cancer treatment.

A DNA risk test could be a low-cost solution that nurses, GPs and other healthcare professionals could perform.

Saya hopes to finish the pilot study by the end of this year.

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