For the longest time, the surest way to confirm a cancer diagnosis entailed cutting pieces of tissue out from the affected area for examination, otherwise known as a tissue biopsy. Even in some cases, such as with certain kinds of lung cancer, where x-rays or MRI scans are sufficient for accurate diagnosis, physicians still require more detailed information in to decide on the best course of treatment.

This is often a source of bother for physicians, who must agonize over whether or not to order a biopsy, because performing an invasive procedure on the patient’s already ailing body is likely to cause complications down the line. It is especially true for lung cancer patients; not only are the lungs themselves hard to access by surgery, but lung cancer patients also tend to be older, which increases the risk of complications from surgery. The biopsy testing itself could take a long time, and drag the overall treatment itself out for even longer. It is these challenges that have driven the medical community to find new ways of confirming the presence of cancer in cells; their success is called “liquid biopsy”.

 

What is Liquid Biopsy?

It entails taking a blood sample of around 10 milliliters from the patient for laboratory investigation. However, the blood sample is not being tested for the presence of cancer cells themselves, but rather the DNA of the cancer cells circulating the bloodstream. This DNA will have mutated to a degree that it can be distinguished from the DNA of ordinary cells. The sample goes through a purification process before being tested with highly sensitive equipment that can make accurate readings from very small samples. The speed of this method allows for timely progression to the next stage of treatment.

This method of diagnosis is hugely beneficial in the treatment of non-small cell lung cancer [NSCLC]) because it enables the conditions for the use of targeted therapy—which directly targets the cancer cells and causes less side effects—to be more quickly identified. The precise nature of these treatment methods requires physicians to have a highly detailed picture of the exact type of cancer cells present in order to select the right kind of targeted therapy.  

At the European Society for Medical Oncology (ESMO) meeting in 2019, the findings of multiple studies drove home the effectiveness of liquid biopsy. Liquid biopsy proved invaluable in the BFAST study, allowing the researchers to identify NSCLC patients with ALK mutations at the similar proportion of those detected with traditional biopsy and provide the patients with more timely and effective treatment.  The US Food and Drug Administration has also approved the use of liquid biopsy to test for the EGFR gene mutation in cancer cells to decide whether to treat NSCLC patients with EGFR tyrosine kinase inhibitor.

The Horizon Regional Cancer Center itself is all too aware of the benefits of this new medical technology. That is why we brought in Thermo Fisher Scientific’s Oncomine™ Pan-Cancer Cell-Free Assay liquid biopsy platform. By conducting the entire biopsy process in-house, we are able to get results faster and at lower cost. This allows physicians to begin treatment sooner than later, while minimizing expenses for the patient. In addition to this, the Horizon Regional Cancer Center is the first and only facility in Thailand capable of testing for gene fusions, a characteristic of certain types of cancer.
 

How will liquid biopsy improve cancer treatment?

At the moment, the use of liquid biopsy is still limited to companion diagnostic tool certain drugs. Nevertheless, the technique itself holds promises for other stages of cancer treatment too, such as early stage cancer diagnosis, even before tumors have formed, since the tell-tale DNA mutations are already circulating in the bloodstream. Liquid biopsy can also be purposed for follow-up checks; if the patient is responding well to treatment, the level of DNA mutations detected in the bloodstream will have decreased. Liquid biopsies can also be used to confirm that a patient is clear of cancer without having to wait for more obvious symptoms to reoccur. There is still a long way to go but researchers around the world are working on these exciting possibilities.

It is no exaggeration to call liquid biopsy an unprecedented breakthrough in the field of cancer treatment due the speed, convenience, and minimal suffering that it affords the patient. Its versatility also bears the promise that it could become a standard procedure in a decade or two, as common and mundane as cholesterol or blood sugar tests. The advance warning that it gives patients means that trouble can be headed off at the earliest possible stages, greatly weighting treatment options towards the realm of prevention.