In general practice, this would determine precision treatment by drugs, but only 9 out of 36 recommended drugs were concordant, or 25%. Another similar study tracking specific genetic mutations found consistent results in only 17% of cases (Chae, et al.)
While these results point to the necessity of using both biopsy methods, tissue biopsies provide more accurate results in some cases. In a study done on pancreatic cancer, tissue biopsies found relevant gene variants in 87% of instances, compared to 25% found by liquid biopsies (Harris). Additionally, liquid biopsies missed the most common pancreatic cancer mutation in 29% of opportunities, compared to 13% missed in tissue biopsies.
At the moment, liquid and tissue biopsies function as two distinct tests with different methods and functions. Using both biopsy methods may prove to be costly and time-consuming. More research and advancement is necessary to conclusively select a superior biopsy. When decisive which biopsy to use, the most likely deciding factor is which phase of the process a patient is in: screening, diagnosis, treatment, remission, or relapse. From there, the best decision can be made.