What is the primary purpose of a liquid biopsy in cancer monitoring?

The primary purpose of a liquid biopsy in cancer monitoring is to detect circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) in body fluids, such as blood. This technique allows for a non-invasive means of analyzing the genetic material shed by tumors into the bloodstream. By isolating and analyzing ctDNA or CTCs, healthcare providers can gain insights into the genetic profile of the cancer, track tumor evolution, assess treatment response, and monitor for recurrence.

Liquid biopsies are particularly valuable because they can complement traditional tissue biopsies by providing a broader picture of tumor dynamics without the need for more invasive procedures. Unlike tissue biopsies, which can only capture a snapshot of the tumor at a specific time and location, liquid biopsies can reflect changes in the tumor's genetic makeup over time, offering a more dynamic view of the disease. This approach is especially useful in cases where the tumor is difficult to access or when a patient is already undergoing treatment.