What about a simple blood test to diagnose many types of solid cancers? Or a blood test that monitors the amount of cancer in a patient's body and responses to treatment?Researchers at Stanford University have designed a new technique that may soon make this a reality.Tumours are called ‘solid’ or ‘liquid’ based on where in the body they grow. More than 80 percent of all cancers are caused by solid tumours that grow as a mass of cells in particular organ, tissue or gland. The new technique called CAPP-Seq (cancer personalised profiling by deep sequencing) is sensitive enough to detect just one molecule of tumour DNA in a sea of 10,000 healthy DNA molecules in the blood.
“We set out to develop a method that overcomes two major hurdles in the circulating tumour DNA field. We are trying to develop a general method to detect and measure disease burden,” said Maximilian Diehn, an assistant professor of radiation oncology at Stanford University's school of medicine.With this upgraded technique, the researchers were able to accurately identify about 50 percent of people in the study with stage-1 lung cancer and all patients whose cancers were more advanced.By developing a general technique for monitoring circulating tumour DNA, the research team is trying to transform solid tumours into liquid tumours that can be detected and tracked more easily.CAPP-Seq may also be useful as a prognostic tool, the researchers found.
The technique detected small levels of circulating tumour DNA in one patient thought to have been successfully treated for the disease; that patient experienced disease recurrence and ultimately died.The researchers are now working to design clinical trials to see whether CAPP-Seq can improve patient outcomes and decrease costs. They are also aiming to extend the technique to other types of tumours like breast, prostate, colorectal and lung cancer.The paper appeared online in the journal Nature Medicine.