Insights derived from FDG PET could improve treatment selection for patients with advanced non-small cell lung cancer.

Italian researches have demonstrated a better way of determining the aggressiveness of tumors in patients with advanced non-small cell lung cancer (NSCLC). In a study presented in the featured clinical investigation article of the November issue of The Journal of Nuclear Medicine, they used 18F-fluorodeoxyglucose (FDG) PET/CT imaging to show that the amount of cell-free tumor DNA circulating in the bloodstream correlates with tumor metabolism (linked to cancer aggressiveness), not tumor burden (amount of cancer in the body).

“Despite the identification of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) as biomarkers capable of providing clinically relevant information in cancer patients, at present their identification is not routinely used in clinical practice,” explained Silvia Morbelli, MD, PhD, of the IRCCS San Martino – IST National Cancer Research Institute and University of Genoa in Genoa, Italy.

This study of 37 patients (24 men and 13 women, ages 51 to 80) who have never been treated with chemotherapy found direct correlation of the amount of cfDNA with tumor metabolism (based on PET-derived parameters), but not with metabolic tumor volume. These results suggest that cfDNA might better reflect tumors’ biological behavior and aggressiveness than tumor burden in metastatic NSCLC.

The researchers noted that a subgroup of 13 patients had metabolically active bone lesions and also higher levels of cfDNA. In addition, while cfDNA correlated with tumor metabolism, no association was found with circulating tumor cells (CTCs). Previous investigations have suggested that cfDNA and CTCs might provide complementary information about tumor biology. The small size of this study means that no definitive conclusions could be made regarding the role of CTCs in NSCLC metabolism.

Morbelli pointed out: “Our findings illustrate the prognostic value of 18F-FDG and provide a deeper understanding of clinically reliable, noninvasive biomarkers that may help identify potential unresponsive NSCLC patients before treatment and limit unnecessary toxicity.”

The article is titled, “Circulating tumor DNA reflects tumor metabolism rather than tumor burden in chemotherapy-naive patients with advanced non-small cell lung cancer (NSCLC): 18F-FDG PET/CT study.”