Interestingly, a recent pooled analysis showed that the location of metastatic site influences the diagnostic accuracy of ctDNA-based EGFR-mutation testing in NSCLC patients, showing higher sensitivity in patients with extrathoracic compared to intrathoracic metastases and implying a better prognosis for the latter subgroup of patients [48]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.