Immunotherapy for small cell lung cancer: current challenges and prospects

Small cell lung cancer (SCLC) is a highly aggressive neuroendocrine malignancy with limited treatment options. While immunotherapy has revolutionized SCLC therapy and now serves as a front-line treatment, the disease continues to present significant clinical challenges. Despite therapeutic advances in lung cancer over the past decade, most SCLC tumors eventually reoccur. Growing insights into the tumor-immune microenvironment (TIME) highlights its critical role in SCLC progression and therapeutic resistance. In this review, we summarize distinctive features of the TIME in SCLC and evaluate current immunotherapeutic strategies, notably immune checkpoint inhibitors (ICIs), that have demonstrated survival benefits in a subset of patients. Furthermore, we explore emerging immunotherapeutic approaches and novel targets in SCLC, emphasizing the challenges limiting the successful application of immunotherapy in this disease.