Association between circulating tumor DNA burden and disease burden in patients with ALK-positive lung cancer.

Analysis of genetic material shed from cancer cells into the circulation offers insights into the molecular composition of tumors. The circulating tumor DNA (ctDNA) varies over time and across individuals and is impacted by the distribution of disease. Herein, the authors estimated tumor burden on imaging and correlated it with ctDNA by calculating the maximum allelic frequency. The current study findings demonstrated that the greatest correlation exists between extrathoracic, extracranial tumor burden (particularly involvement of the liver, adrenal glands, or bones) and ctDNA burden, suggesting a biological basis for the interpatient and temporal intrapatient differences in ctDNA yield that have been described in previous studies.