Despite being the diagnostic standard, tissue biopsy has real limitations that patients and clinicians need to consider:

Invasiveness and risk: As a procedure involving needles, surgery, or endoscopy, it carries risks such as bleeding, infection, pain, and, depending on the site, risks specific to the organ being sampled
Limited to one location: A tissue biopsy samples only the specific site from which it is taken, which may not reflect the full genetic picture of a tumor if the cancer is heterogeneous or has spread to other areas, an issue known as tumor heterogeneity
Not always repeatable: Because it is invasive, it is difficult to repeat frequently to monitor how a cancer is responding to treatment over time, unlike a blood-based liquid biopsy
Accessibility challenges: Some tumors are located in areas that are difficult or dangerous to reach with a needle or surgical instrument, making biopsy technically challenging or risky
Insufficient sample size: Sometimes the amount of tissue collected is too small to complete all necessary molecular and genetic testing, requiring a repeat procedure
Processing time: Tissue biopsy results, particularly detailed molecular and genetic testing, can take longer to process compared to some liquid biopsy panels, which may delay treatment decisions in urgent situations