Small Cell Lung Cancer in Transition: Recent Advances in Biology, Treatment, and Precision Medicine.

Small cell lung cancer (SCLC) is a highly aggressive neuroendocrine malignancy associated with rapid proliferation, early metastatic spread, and poor long-term survival. Despite high initial responsiveness to chemotherapy and radiotherapy, most patients experience relapse, and therapeutic progress historically remained limited. Recent years, however, have seen meaningful advances that are beginning to reshape the management of SCLC. In extensive-stage disease, the incorporation of PD-L1 inhibitors into platinum-etoposide chemotherapy has established chemoimmunotherapy as the first-line standard, while underscoring the continued need for more durable disease control. In limited-stage SCLC, consolidation durvalumab following concurrent chemoradiotherapy has emerged as a practice-changing strategy with significant survival benefit. In relapsed disease, DLL3-targeted therapy has opened a new therapeutic avenue, with tarlatamab demonstrating clinically relevant efficacy in previously treated extensive-stage SCLC and becoming the first approved bispecific T-cell engager in this setting. Alongside these milestones, ongoing investigation is focused on maintenance strategies, novel targeted agents, biomarker development, molecular subtyping, and more effective integration of systemic therapy with radiation-based approaches. Nevertheless, resistance, toxicity management, central nervous system involvement, and the absence of validated predictive biomarkers remain major barriers to sustained progress. This narrative review examines recent advances in the biology and clinical management of SCLC, with emphasis on practice-changing developments, emerging therapeutic platforms, and future strategies aimed at improving outcomes in this historically difficult-to-treat disease.