A group of European researchers and Thermo Fisher Scientific found that next-generation sequencing-based blood tests were able to detect and monitor the progressively changing genetics of lung tumors—illustrating developments in drug resistance over time, while showing results comparable to tissue biopsies.
In a retrospective study, 88% of a group of 94 patients with non-small cell lung cancer presented the same clinically relevant genetic mutations in tissue and plasma samples taken at the same time during diagnosis. However, that concordance began to drop, down to 72%, among additional liquid biopsies performed as time went on.
The researchers, from University Hospital Basel, the University of Porto and the Hospital of Sao Joao, said they believe the slowly diverging results were due to genetic drift, caused by new mutations forming during treatment.
“It can take several weeks to months to observe visible signs of relapse when you’re monitoring for disease progression using radiological scan,” study co-author Luca Quagliata, Ph.D., global head of medical affairs for clinical NGS and oncology at Thermo Fisher, said in a statement. “In contrast, multiple studies have highlighted that liquid biopsy can identify genetic markers associated with resistance to treatment even before clinical signs manifest.”
“Following that direction, our results show that liquid biopsy NGS can provide early insights on tumor progression, thus offering a powerful tool for noninvasive longitudinal cancer monitoring to guide the care team on the best course of treatment moving forward,” Quagliata said. The study, employing Thermo Fisher’s Oncomine platform, was presented at the European Association for Cancer Research’s Joint Conference on Liquid Biopsies in Bergamo, Italy.
Additionally, the blood tests were able to spot tumor mutations such as EGFR, ALK and BRAF that were not present in the initial tissue biopsies from 45% of patients—attesting to the heterogeneity of cancer and the benefits of using liquid biopsy in patients with multiple metastatic tumors. Overall, researchers were able to detect variants in nine different clinically targeted genes.