Decoding the enigma of multiple primary lung cancers: from mechanism to bedside-a narrative review

Lung cancer is the leading cause of global cancer mortality. Multiple primary lung cancer (MPLC) represents a clinically challenging subtype characterized by independent tumor foci. Distinguishing MPLC from intrapulmonary metastases is crucial for prognosis and treatment. This review integrates current evidence on MPLC's etiology, molecular mechanisms, diagnosis, and management, aiming to provide a clinical reference and highlight future precision medicine directions.

We searched PubMed/MEDLINE, Web of Science, and Google Scholar for articles published between January 2000 and September 2024. Search terms included "multiple primary lung cancer", "diagnosis", "molecular characteristics", and "treatment". The selection focused on English-language research and reviews addressing MPLC pathogenesis, diagnosis, or management.

The review delineates the multifactorial pathogenesis of MPLC, encompassing genetic susceptibility, somatic heterogeneity, clonal evolution, and epigenetic dysregulation. It frames these mechanisms against a backdrop of "field cancerization" and dynamic tumor microenvironment interactions. The evolution of diagnosis from histology to integrated molecular-artificial intelligence (AI) models is detailed, alongside treatment strategies that must overcome the challenge of inter-lesional heterogeneity.

MPLC is a distinct entity arising from genetic, epigenetic, and microenvironmental interplay. Advancing its management requires multi-omics integration to decipher pathology and identify biomarkers. Future work should develop AI-enhanced diagnostics and lesion-specific treatment strategies. This review synthesizes current evidence to inform and direct future research and clinical innovation in MPLC.