An annual blood test for eight common cancers could soon become part of Australians' regular health check-up, revolutionising early detection for the deadly disease and potentially saving thousands of lives.
In a major breakthrough, researchers say they have developed a test that can identify eight types of early cancer in the period before they spread to the rest of the body.
The test screens for ovarian, liver, stomach, pancreatic, oesophagus, colorectal, lung and breast cancers - diseases collectively responsible for more than half the cancer deaths in Australia each year.
Last year they killed an estimated 25,000 people.
The test, dubbed CancerSEEK, offers particular hope for pancreatic cancer, because it is notoriously difficult to diagnose in its earlier stages. As a result, more than nine out of 10 people with the disease die within 5 years of being diagnosed.
But the researchers said there was a "wide window of opportunity to detect cancers prior to the onset of metastasis."
"For many adult cancers, it takes 20 to 30 years for incipient neoplastic lesions to progress to late-stage disease."
Although the test was not able to pick up all early stage cancers, identifying 70 per cent, it had a very low false positive rate of less than 1 per cent.
The study was led by a team of US researchers from Johns Hopkins University.
It also involved more than 400 patients from Melbourne's Footscray Hospital and two Australian scientists from the Walter and Eliza Hall Institute, Associate Professor Jeanne Tie and Professor Peter Gibbs.
Professor Gibbs said he envisaged that the test would be widely used for annual screening of older Australians more susceptible to cancer, aged about 50 to 75.
"It's also a test you would do in young people if they had a strong family history, or any other risk factor for cancer," he said.
"Because it's a blood test, it's fairly simple, we could do it quite frequently ??? likely once every 12 months."
Professor Gibbs said a new larger study involving 10,000 people in the United States was now underway to confirm CancerSEEK could save lives, although the consumer demand would probably be so great that it would become commercially available before that work was complete.
"It is probably about $1000 to do it at the moment," he said.
"It's likely over the coming years it will drop down to a few hundred dollars."
The closest similar test presently available is the PSA test, said Professor Gibbs. But it only tests for prostate cancer, and has been controversial because of its high rate of false positives (around 9 per cent).
The new tests screens for key proteins and gene mutations that indicate the presence of cancer, and is also able to identify the location of the cancer in many cases.
One person that could benefit from the new blood test is Melbourne mother-of-two Melissa McIlvain.
The 30-year-old inherited the BRCA1 gene mutation passed through four generations, meaning that she is at high risk of developing both breast and ovarian cancer. Her grandmother also died of pancreatic cancer.
Ms McIlvain said she was planning to have a double mastectomy reconstruction within the next two years.
"Basically I'm going to get both my breasts removed and reconstructed so that my chances of breast cancer goes down significantly," she said.
But it was harder to plan for ovarian cancer.
"I'm a lot more worried about the ovarian cancer because there's less protection, so just the fact there's going to be some kind of early test to discover it earlier is very exciting for me," Melissa McIlvain said.
She also has another reason to hope for better screening options in the future, as her daughters, Ava, 3, and Kaylee, 14 months, have a 50 per cent chance of possessing the BRCA1 mutation.
Professor Gibbs said it was difficult to predict how many lives the test could save.
"But if we could reduce cancer deaths by 20 to 30 per cent across those major cancers it would a really big advance."
In Australia, that would translate to more than 7000 lives saved each year.