By Divyen Patel, PhD
A biopsy is a medical procedure in which clinicians remove a piece of tissue or a sample of cells from a patient’s body for testing in a pathology laboratory to determine if that patient has cancer or another condition such as an infection or autoimmune disease. The most common form of biopsy has been tissue biopsies, in which a clinician extracts solid tissue for testing through a needle or by cutting a sample from the patient.
While tissue biopsies remain extremely reliable in diagnosing cancer and other diseases, their usefulness is limited. For one, they can only tell clinicians whether a patient currently has cancer. Further, tissue biopsies are not always simple in-office procedures. Many involve open surgery and can be risky, painful, and expensive. In addition, some patients may be poor candidates for tissue biopsies due to the location of their tumors or the existence of a complicating health condition. These barriers make it difficult to track the development of a disease through multiple tissue biopsies taken over time.
This is where another type of biopsy—liquid biopsies—is proving to be invaluable. Liquid biopsies are not new; they have been used for years to detect tumor material in bodily fluids. As cells die, fragments of DNA are shed into a person’s blood. Liquid biopsies can detect this circulating DNA in the earliest stages of the disease, well before a tumor has begun growing.
The clinical value of early detection
Without early detection, tumors usually grow without the patient noticing or displaying any symptoms. By the time the patient has symptoms, lesions may have grown to sizes that obstruct blood vessels or internal organs, frequently making them inoperable and forcing clinicians to resort to chemotherapy drugs and radiation. These traditional treatments can have serious side effects for patients, including fatigue, anemia, nausea, infection, constipation, and other adverse symptoms. In some cases, chemotherapy and radiation can be fatal.
Liquid biopsies give clinicians and patients the chance to sidestep all of the above. Imagine a young woman from a family that has a documented history of mothers developing breast cancer. Liquid biopsies allow clinicians to monitor the woman every six months or annually to check if a tumor is forming and treat it before it grows.
Liquid biopsies also make it easier to monitor a disease’s progress. Once a cancer is detected, periodic liquid biopsies can be used to determine if it has changed, allowing clinicians to treat the cancer that exists now rather than the one at presentation. This is critical because cancers, by nature, are always mutating.
Emerging applications of liquid biopsies promise to revolutionize treatment of cancer and other diseases. Researchers are using liquid biopsies to analyze a patient’s blood for the presence of biomarkers that indicate not just the existence of cancer, but a patient’s predisposition to certain cancers. Should a patient’s blood show biomarkers indicating the presence of a cancer—which can occur even before a mass develops—clinicians can immediately begin a course of preventive treatment.
One panel now under development contains 146 genes and can tell clinicians if a patient is predisposed to 88 different cancers. It is only a matter of time before this panel is commercialized and can be offered as a service. When it is, the ramifications will be enormous for cancer prevention and treatment. Also, blood is not the only bodily fluid to which liquid biopsies can be applied. Researchers are developing methods for analyzing urine to test for the presence of prostate cancers, an application expected to be available soon.
Genetic information gleaned from advanced applications of liquid biopsies could dramatically improve individual and population health outcomes while lowering healthcare costs for patients and our healthcare system. According to the National Cancer Institute (NCI), the economic burden associated with cancer care for patients and their families in 2019 was $21.09 billion (with out-of-pocket costs of $16.22 billion and patient time costs of $4.87 billion). NCI estimates the overall cost of cancer in the U.S. at $209 billion in 2020.
Though most new applications for liquid biopsies are focused on detecting cancers and predisposition to cancers, these advances eventually will be used to help identify and proactively address conditions such as amyotrophic lateral sclerosis or Alzheimer’s disease.
NCI is supporting efforts to develop public-private partnerships to develop liquid biopsy applications for detecting early-stage cancers and screening Americans who are considered high risk because of the prevalence of cancers in their families.
The collaborative work between facilities, research institutions, academic centers, pharmaceutical and biotech companies, oncologists, and pathologists to develop applications for liquid biopsies in treating cancers and other genetically based diseases is ongoing and promises to lead to historic advances in genetics-based medicine. The result will be far better outcomes and a sharp reduction in the cost of healthcare. That exciting future is right around the corner.
Divyen Patel, PhD, is chief research officer for Tesis Biosciences, the leading provider of genetic sequencing and precision medicine tools for creating personalized care plans for treating chronic diseases individually and across generations. Patel is also the founder of Genome Explorations, a premier research institution providing global genomic profiling and molecular diagnostic services that was acquired by Tesis earlier this year.