Scientists create blood test for cancer detection

Scientists create blood test for cancer detection

Hopes have been raised that a simple blood test could one day be used to detect cancer following success in a research project.
 
Scientists at the Johns Hopkins University in Baltimore and the Memorial Sloan-Kettering Cancer Centre in New York have published the results of the CancerSEEK blood test, which examines markers in the blood to see if a person has the disease or not.
 
They focused on cancers of the ovaries, liver, stomach, pancreas, oesophagus, colorectum (bowel), breasts and lungs and looked for small fragments of DNA circulating in the blood that come from tumours.
 
Protein biomarkers were also analysed, since some early tumours do not release enough DNA into the blood to be picked up in a test.
 
The team looked at a total of eight protein biomarkers and mutations at more than 2,000 locations in the DNA, as well as using the data to see if they could ascertain where tumours were located.
 
Some 1,005 people with non-metastatic cancer were involved in the study, plus another 812 healthy people with no known cancers to act as a control group.
 
It was found that the test was able to correctly identify people with cancer at a rate of 70 per cent sensitivity - and 99 per cent of those who generated a positive test result did have cancer.
 
This means that not only is it the most accurate test seen so far, but it is unlikely for people to receive a false positive when it is used.
 
However, the researchers conceded in the journal Science that the proportion of cancers detected was higher in some types of the disease than in others. For example, it was significantly more accurate for liver and ovarian cancer than it was for breast cancer.
 
This means it would need to be improved before it could be used as a screening tool, particularly where cancers are in their early stages. The test would also need to be assessed to see whether other diseases have an impact on accuracy and could generate false positives.
 
Nevertheless, the medical world has reacted with tentative excitement to the news, recognising its huge potential in future.
 
Dr Cristian Tomasetti from Johns Hopkins University School of Medicine told BBC News: "I think this can have an enormous impact on cancer mortality. We envision a blood test we could use once a year."
 
Dr Gert Attard from the Institute of Cancer Research added: "I'm enormously excited. This is the Holy Grail - a blood test to diagnose cancer without all the other procedures like scans or colonoscopy."
 
In future, it may be that cancer tests can be carried out at healthcare providers such as pharmacies in order to provide better care for patients.
 
Currently, although cancer survival rates have doubled over the past 40 years, there remains disparity between them where different types of cancer are concerned.
 
For example, while 78 per cent of breast cancer patients can expect to survive for ten years or more, the same figure for pancreatic cancer patients is less than one per cent.
 
It may be that a simple blood test can change all this.