For more than 40 years, oncologists prescribed “empiric” chemotherapy for cancer patients, using their experience and instincts to search for the right combination of drugs to kill or, at least, prevent further multiplication of cancer cells. This was the norm given the absence of a more precise understanding of the specific makeup of tumors.
Today, thanks to genetic analysis of tumors, we’re able to identify the genes responsible for the oncogenesis and spread of a tumor and can be more targeted in our treatment. Until now, what we learned through next generation sequencing (NGS, a survey of the genome in search of anomalies), the most widely used technology, was sometimes hampered by not having enough tumor tissue required to perform the genetic analysis.
Additionally, with tumors being heterogeneous, different areas of a suspicious solid mass could contain more cancer cells than others, even within the same sample or when comparing several samples from the same patient.
A Better Way
Tumors release DNA into the bloodstream that can be collected via a blood test, separated from the plasma, and studied. The circulating tumor DNA (ctDNA) and intact circulating tumor cells (CTCs) are two of the targeted components during what is known as a liquid biopsy.
While we’ve been able to extract DNA from identified tumor cells and study its molecular makeup since the 1980s, we haven’t been able to combine that with NGS until now. This is a quantum leap in our field, resulting in the delivery of critical information within two weeks (as opposed to the four or five required for tissue analysis) that isn’t affected by tumor heterogeneity.
The offshoot of all this is that we can now use liquid biopsies and NGS to evaluate patients at several different points of their cancer treatment, making adjustments in their chemotherapy based on new anomalies we discover. A more precise style of medicine, it enables us to develop targeted agents to kill specific cancer tumors with drugs proven to be effective, curing some patients and potentially improving the quality of life for all.
This approach, available in several platforms, is commercially viable for cancer care and recently approved for reimbursement by the Centers for Medicaid and Medicare Services (CMS).
At Memorial Cancer Institute, we’re having success using liquid biopsies to diagnose and evaluate new cancer patients (especially those with lung cancer) where we’ve identified nine genes that are known to cause the disease. We have targeted treatments for each and can personalize therapy per patient.
Maria's Success Story
Datasource: Maria's lung cancer story
Maria, a 41-year-old stage IV lung cancer patient, is someone who recently benefited from this technology. Since there are no warning signs for lung cancer, she, like 60% of the lung cancer patients we see, presented to us at a later stage. Her liquid biopsy uncovered an ALK fusion, which told us the best treatment for her cancer would be to receive an oral agent (which was successful) instead of palliative and empiric chemotherapy.
She responded well to targeted therapy and didn’t need further chemotherapy.
I'm still young, have a wonderful family, a wonderful life, and am confident the research is going to give me many more years.
The possibilities with liquid biopsies are endless. In the future, we are hopeful they can be used to predict recurrences of cancer in patients who have had surgery. Taking its potential a step further, it’s possible we could diagnose cancer through blood testing that would identify DNA alterations. This early-stage diagnosis could happen even before the patient experiences symptoms or gets radiology findings.
It wouldn’t be surprising if liquid biopsies completely replace tissue biopsy at some point in the not-too-distant future.