A new study suggests that blood test may be able to save lives by finding cancers that have started to grow again after treatment.
Using the test, scientists at the Institute of Cancer Research in London found traces of breast cancer eight months before doctors would normally have noticed. In the trial, the test found 12 cancers out of the 15 women who relapsed. Experts said there was still some way to go before there was a test that could be used in hospitals.
Surgery to remove a tumor is one of the core treatments for cancer. However, a tumor starts from a single cancerous cell. If parts of the tumor have already spread to another part of the body or the surgeon did not remove it completely, then the cancer can return.
The hope is that detecting cancer earlier means treatments including chemotherapy can start sooner and improve the odds of survival. The analysis of the blood is relatively cheap. However, investigating the DNA of the tumor for mutations in the first place is still expensive.
The price is coming down as the field of cancer medicine moves from treating tumors in whichever part of the body they are discovered, towards drugs that target specific mutations in tumors.
Finding less invasive ways of diagnosing and monitoring cancer is really important and blood samples have emerged as one possible way of gathering crucial information about a patient's disease by fishing for fragments of tumor DNA or rogue cancer cells released into their bloodstream.
But researchers admit that there is some way to go before this could be developed into a test that doctors could use routinely, and doing so is never simple.