Combined small cell lung cancer: current progress and unmet needs.

Combined small cell lung cancer (CSCLC) is a specific subtype of lung cancer characterized by a pathological mixture of small cell lung cancer and any subtype of non-small cell lung cancer components. Currently, our understanding of the clinicopathological features, origin, molecular characterization, treatment, and prognosis of CSCLC remains limited. CSCLCs represent examples of intratumor heterogeneity and pose challenges for accurate diagnosis. Are there any distinct clinicopathologic and molecular differences between pure SCLC and CSCLC? Furthermore, the prognostic outcomes and optimal treatments for CSCLC are urgently needed. This article aims to summarize the current biological features and clinical management of CSCLC, providing a reference for further understanding of this heterogeneous form of small cell lung cancer.