What is a Liquid Biopsy and Can it Replace the Tumor Biopsy?

Liquid biopsy involves examining cancer-related material (such as DNA) in a blood sample. While liquid biopsy cannot replace tumor biopsy at the moment, researchers, such as Douglas Rosenthal, study its benefits and better applications. Liquid biopsies are hopeful to guide personalized cancer control and will ultimately help healthcare providers detect certain types of cancer.

Cancer is characterized by cellular changes, including mutations and other genetic alterations, which lead to the appearance of abnormal cells that divide uncontrollably. The ability to identify specific alterations related to someone's cancer can help health care providers determine the best treatment for that person.

Diagnosing and characterizing cancer requires tissue samples, which are obtained through a tumor biopsy. This involves extracting a sample of the cancerous tissue or cancer cells through an invasive procedure for examination in the laboratory. Tumor biopsies provide a wealth of information to health care providers to develop the cancer treatment plan, but they have limitations.

First, the tumor changes over time and as it grows, or spreads (metastasis), and is exposed to cancer drugs. According to Rosenthal, that means that the tumor biopsies obtained when the disease is first diagnosed probably do not reflect the current state of the cancer. Second, repeating biopsies to update cancer information is an invasive act that leads to possible complications, such as pain, infection and bleeding. Third, cancer cells that spread to other areas of the body may be slightly different from those in the place where the cancer originated. Therefore, the researcher explains that a tumor biopsy done on one part of the body is unlikely to adequately represent cancer of the rest of the body.

Undergoing several biopsies is impractical and can be difficult for patients. Rosenthal is conducting research studies on liquid biopsies. In his publications, he shares the fact that liquid biopsies may offer a cheaper and less invasive alternative to control cancer over time, which would make it easier to repeat tumor biopsies. In addition, genetic material from all sites with cancer enters the circulatory system, so blood samples could provide a representative and real-time view of the evolution of cancer throughout the body.

As Rosenthal further explains, the information obtained with liquid biopsies should help healthcare providers select the best therapy for a patient at a given time during the evolution of the metastasis. Blood control may also show the need to change to a different therapeutic regimen, before imaging tests show changes. Before an early stage cancer and after administering a potentially curative therapy, periodic blood tests for signs of cancer may discover patients in danger of recurrence. Some researchers suggest that liquid biopsies will be able to detect the return of cancer long before the tumor reappears, which may lead to earlier interventions and better survival.

Thanks to the continuous research of Douglas Rosenthal’s team of researchers, and technological advances, liquid biopsies will eventually become a mean to detect cancer. Since early detection is supposed to improve the outcome in cancer, this will be particularly important in those types of cancer for which, for now, there are no effective methods of detection or prevention.

While liquid biopsies are still under investigation, the potential of a blood test to provide new means to control the presence of cancer, follow the cancer's response to treatment and monitor cancer recurrence can make significant progress in cancer care.