Dr Hirsch on the Benefits of Tissue vs Liquid Biopsy in NSCLC

Fred R. Hirsch, MD, PhD, executive director, Center for Thoracic Oncology, The Tisch Cancer Institute at Mount Sinai; Joe Lowe and Louis Price Professor of Medicine (Hematology and Medical Oncology), Icahn School of Medicine at Mount Sinai, discusses the pros and cons of completing a tissue biopsy compared with a liquid biopsy in non–small cell lung cancer (NSCLC).

Tissue biopsy remains an essential method for determining molecular characterization, despite the advancements in liquid biopsy technology, Hirsch begins. Solid tissue samples provide crucial insights into tumor biology that are not yet fully replicated by liquid biopsy methods, he says. The primary advantage of tissue biopsy lies in its ability to offer a comprehensive and detailed analysis of the tumor's molecular profile, which is critical for accurate diagnosis and guiding treatment decisions, Hirsch explains. Tissue biopsies allow for the examination of the tumor's histology, architecture, and cellular environment, providing information that is vital for identifying specific mutations and understanding the tumor's behavior, he adds.

However, liquid biopsy technology has made significant strides and provides a less invasive alternative to tissue biopsy, Hirsch states. Liquid biopsies involve the analysis of circulating tumor DNA (ctDNA) and other biomarkers found in the blood, providing a snapshot of the tumor's genetic landscape. The main challenge with liquid biopsies lies in their sensitivity, Hirsch says. Although a positive liquid biopsy result is highly reliable, with specificity approaching 100%, the interpretation of a negative result is more complex. The current sensitivity of liquid biopsy assays is around 80%, meaning that some mutations may not be detected, potentially leading to incomplete or inaccurate assessments of the tumor, he details.

To overcome these limitations, many institutions, including Mount Sinai, are adopting a parallel approach, Hirsch says. This involves conducting both tissue and liquid biopsies simultaneously at the primary diagnosis stage. This dual approach helps to mitigate the shortcomings of each method, he explains. For instance, there are cases where a liquid biopsy detects a mutation that a tissue biopsy misses, which can occur due to tumor heterogeneity or insufficient tissue samples, he notes. By using both methods in conjunction, the likelihood of accurately identifying mutation increases, leading to better-informed treatment decisions, Hirsch concludes.