The Clinical Use of Genomic Profiling to Distinguish Intrapulmonary Metastases From Synchronous Primaries in Non-Small-Cell Lung Cancer: A Mini-Review

The ability to reliably distinguish synchronous primary non-small-cell lung cancer (NSCLC) from intrapulmonary metastatic spread affects staging and treatment decisions in resected NSCLC. Adjuvant therapy for early-stage NSCLC is complicated and recommendations are primarily based on older data from trials that used now-outdated staging systems. Patients found to have 2 tumors with similar morphology in the same lobe are currently staged as pathologic T3 (pT3) but such cases represent a minority of patients in adjuvant lung cancer trials. Potentially more precise than tumor morphology alone, comprehensive genomic profiling technologies have the power to discriminate whether tumors in the same lobe represent 2 separate primary lesions or localized spread of a single lesion. In addition to lineage insights, tumor profiling simultaneously provides information on actionable genomic alterations. In this review we discuss the data that support the ability of molecular technologies to distinguish synchronous primary tumors from intrapulmonary metastases and discuss the use of molecular assays as an adjunct to current staging systems. Two cases are presented to highlight the potential immediate clinical implications of comprehensive genomic profiling.