Targeted agents in the management of small cell lung cancer - present and future.

Lung cancer is the leading cause of cancer-related mortality worldwide and is the second most common cancer in both sexes. The small cell lung cancer (SCLC) subtype constitutes about 13% to 15% of all diagnosed lung cancers with an expected 5-year mortality of about 90%. In the past decades, various strategies used to treat newly diagnosed, relapsed or refractory SCLC have shown no significant improvement in clinical outcomes. In the genomic era of oncology, with a better understanding of tumor biology and pathway specific investigations, multiple investigational agents have been studied with the aim to improve clinical outcomes. Some of them include epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), BCR-ABL TKIs, mammalian target of rapamycin (mTOR) inhibitors, vascular endothelial growth factor (VEGF) inhibitors, etc. All of them have been unsuccessful in adding any survival advantage. DNA repair inhibitors, immunotherapies and anti-delta-like protein 3 (DLL3) antibody-drug conjugates have also been tested so far. This article aims to review the current literature and investigational approaches to improving clinical outcomes of SCLC.