Tech Trends: Liquid Biopsy for Genetic Testing in Lung Cancer
When it comes to cancers, there is nothing more important than offering the right diagnosis and treatment at the right time. Among all cancers, lung cancer has the highest burden, accounting for the largest number of deaths according to WHO. In 2016, the US FDA approved a liquid biopsy test — the cobas EGFR Mutation Test v2 by Roche — as a companion diagnostic for metastatic non-small cell lung cancer (NSCLC).
Traditional Biopsy vs. Liquid Biopsy
A traditional biopsy is an invasive procedure to collect a piece of tumour tissue. It requires local anaesthesia, causes discomfort to the patient, and may not always be feasible because of the location of the tumour.
A liquid biopsy is essentially a blood draw. The blood samples are spun down to collect plasma and to isolate DNA shed by the tumour into the bloodstream — the circulating free tumour DNA (cfDNA). Technology advancements today enable geneticists to analyse small amounts of cfDNA for mutations related to a specific disease.
Why This Matters for Lung Cancer
Erlotinib (Tarceva) is a targeted therapeutic in metastatic NSCLC treatment. Patients with mutations in exon 19 (deletions) or exon 21 (substitutions) in the EGFR gene are selectively chosen to be treated by this drug — these mutations are present in 10–20% of NSCLC patients. The liquid biopsy test identifies these patients from a simple blood draw, without the need for an invasive tissue biopsy.
Another great advantage is real-time monitoring of disease progression — as tumours evolve and may need different treatments based on the genetic changes that occur within them, liquid biopsy enables rapid, repeated testing.
Becoming the New Standard of Care
“The use of circulating free DNA collected from blood [liquid biopsy] to determine which treatment a cancer patient should receive is already a reality, and will begin to change the way we diagnose and treat patients in future. We will likely see liquid biopsies becoming a standard of care for some cancer types.” — David Solit, MD, Precision Medicine Expert, Memorial Sloan Kettering Cancer Center
Precision Oncology Starts with Genetic Testing
MapmyGenome offers Oncomap — a comprehensive hereditary cancer risk panel — as well as molecular diagnostics and certified genetic counselling for individuals with a personal or family history of cancer. CAP & NABL-accredited laboratory.
