Although in their infancy, liquid biopsies are proving to be a promising procedure for safe, quick, and effective cancer screening, detection, and monitoring. Liquid biopsy tests are conducted on blood samples that examine biomarkers shed by tumors such as cancer cells or pieces of tumor DNA present in the body fluids of patients with cancer. 

Liquid biopsies offer a less invasive alternative to diagnose and monitor cancers that provide quicker results than tissue biopsies or imaging scans. Often a liquid biopsy is used if a tissue biopsy is not possible due to the location of the tumor. Most commonly this method is used to identify and monitor changes in patients with non-small cell lung cancer (NSCLC) but is also now being considered for other types of cancer, including breast, ovarian, and prostate; as well as to track cancer recurrence in patients who have previously received cancer treatment, and for early detection for cancers that are often more challenging to identify early, such as head, neck, pancreas, lung, and bowel cancers.  

For patients who have undergone cancer treatment, to check their status, they would typically have to have pet scans and cat scans, but these tests don’t get down to the minutiae of small cells that could still be growing in the body. Any of these cells have circulating tumor antibodies and DNA that can be picked up with a blood test. Liquid biopsies make it possible to follow without having to re-operate or use radiation tests to indicate whether or not something is going on. From that point, patients can be looked at closer with tissue biopsy or imaging testing as needed. 

Liquid biopsies can also be used in screening situations for patients that are high-risk, due to chemical exposure, carcinogens, etc. Individuals who fall under this category should seek discounted or free screening now  as liquid biopsies are still being tested, so there are many offers available. Independent municipalities have offered free test coverage for high risk individuals – like firefighters, EMT, etc. (based on union contracts. Other offers can be found for individuals participating in research studies through university programs or directly with the manufacturing companies.

Although liquid biopsies are not foolproof just yet, continued testing is proving that the whole package is a much safer alternative for patients and an exciting development for cancer research and treatment. 

The latest phase of one such trial, will evaluate the use of circulating tumor DNA (ctDNA) to guide chemotherapy treatment decisions after curative surgery in patients with early stage colorectal cancer. The TRACC (‘Tracking mutations in cell free DNA to predict Relapse in early Colorectal Cancer’) trial intends to spare unnecessary chemotherapy if the patient tests negative for ctDNA. 

Professor Stan Kaye, consultant medical oncologist at the Royal Marsden NHS Foundation Trust said, “This may translate into early diagnosis for the general population, where a simple blood test or liquid biopsy can detect cancers up to 8 months before they become symptomatic.”