While using ctDNA is emerging as a useful technique in oncology, it still has many drawbacks.
Liquid biopsies are not used as a preventative tool yet. They are not recommended for healthy people visiting the doctor. As a result, early detection of cancer is not commonplace, unless there is another persistent problem for which the biopsy was recommended.
Tracking ctDNA is also prone to false negatives and false positives. A false positive occurs when the sample indicates cancer, even if no danger is actually present – because the tumor has already been caught and eradicated by the immune system, or because it continues to grow so slowly that it will not harm the patient in his or her lifetime. False positive results can lead to overtreatment, which may cause harm to the patient.
Another consistent challenge in research has remained: certain cancers have very low or inconsistent cell death patterns, making them difficult to track (Kato et al.) Liquid biopsies can detect ctDNA, but not always the point of their origin. Extensive follow-up may be required to pinpoint an exact location.
There is no standardization in the industry yet regarding ctDNA testing. While there are many kits available for the liquid biopsy, all of the methods are different and provide results designed for various needs. Investment and standardization of the current techniques are required to make ctDNA testing accessible to all patients in a cost-effective way.