Blood test to detect cancer

A PERSONALISED blood test can tell whether a patient's cancer has spread or come back, offering a better way to see if treatments are working, US researchers said on Thursday.

Having a test that can detect tumors in the blood could help doctors customise cancer treatments, offering more aggressive therapy to some patients while sparing others from unneeded chemotherapy or radiation.

'We're talking about what could be a management tool for a number of patients,' said Dr. Bert Vogelstein of Johns Hopkins University in Baltimore and the Howard Hughes Medical Institute, who worked on the study published in the journal Science Translational Medicine.

The gene-based test takes advantage of rapid advances in the technology to sequence whole genomes - all of a person's genetic code - once a very costly and time-consuming task.

'This is really personalised medicine. This is not something off the shelf,' Dr. Vogelstein said in a telephone interview. 'This is something that has to be designed for each individual patient.'

For the study, the researchers took six sets of normal and cancerous tissue from four colorectal and two breast cancer patients, and mapped out the genetic code in each. In the cancer samples, the team looked for areas in the genetic code where there were extra DNA copies, or where sections of chromosomes had fused together.