Scientists have said that a simple, quick blood test may soon become available to diagnose cancer and indicate how far advanced the condition is.
Thus far, test to monitor the levels of tumour DNA in the blood have lacked sensitivity and been time consuming.
Researchers based at Stanford University School of Medicine have had success in the development of a test which will allow doctors to quickly detect the size of the tumour, its response to treatment and its evolvement over certain periods of time.
The medics have stated that the new test is suitable for testing for the most common types of the disease, including prostate, lung and breast. It may also be used to screen at-risk or healthy patients for signs of the disease.
Cancer cells are constantly dividing and dying. During this process, it releases DNA into the patient’s bloodstream and this can be used during blood tests. However, even those patients who suffer from very advanced cancer will only indicate low amounts of DNA in their bloodstream. This has made the creation of a detection test quite difficult.
Dr Maximilian Diehn, an Assistant Professor of Radiation Oncology, said that they had set out to develop a suitable method to try and overcome two of the main hurdles in the circulating tumour DNA practice. The first was that the technique had to be extremely sensitive to allow it to detect the tiny amounts of tumour DNA within the blood. The second was that for it to be useful on a clinical level, it was necessary to offer an off-the-shelf test for patients with a specified cancer.
Dr Ash Alizadeh, Assistant Professor of Medicine, added that their intention was to develop a general method for the detection and measuring of the burden of the disease. He said that it was easier to monitor cancers such as leukaemia, rather than solid tumours, by having easy access to the blood. By the development of a general method of monitoring the tumour DNA that is in circulation, they are effectively trying to transform solid tumours into liquid which is able to be detected and tracked in an easier fashion.
The researchers may have placed focus on those patients who suffered with non-small-cell lung cancer, but the method should be suitable for different solid tumours within the body.
The new method of testing should also have the capacity to identify if the cancer is developing resistance to certain treatment methods. This allows doctors to modify the treatment plan.
Dr Diehn further stated that if they have the opportunity to monitor the tumour’s evolution and be given the opportunity to identify subclones that have become treatment-resistant, they had the potential to switch or add therapies to target specific cells.
He said that they would also be able to identify subsets of patients who were in the early stages of the disease and may gain benefit from additional treatments after radiation or surgery, such as immunotherapy and chemotherapy. They may have the opportunity to develop assays with the capacity to screen for multiple cancers.
The full study has been published in the Nature Medicine journal online.
Image credit: Neeta Lind