Update on targeted therapies for small cell carcinoma of the lung

Small cell lung cancer (SCLC) is an aggressive malignancy with a poor prognosis. It can be very sensitive to radiation and cytotoxic chemotherapy and is potentially curable if all sites of disease can be encompassed in a radiation field. For the vast majority of patients relapse is the norm, with only limited gains from further lines of chemotherapy. In spite of the recognition of a number of molecular targets based on preclinical studies, targeted therapy for small cell lung cancer has yet to demonstrate any significant clinical benefit. This review summarizes the various targeted pharmacological approaches employed with a view to extending survival in extensive stage SCLC or improving on remission induction in limited stage disease. Pharmacological agents have targeted aberrant signal transduction pathways, proteins involved in cell cycle progression, apoptosis and angiogenesis. Additionally, immunomodulatory approaches have been used to stimulate an immune response against tumor associated antigens. Though the clinical data thus far is discouraging, drugs are still undergoing evaluation and more targets continue to be identified. There is considerable scope for further research and in particular combining newer therapies with existing treatment modalities to improve outcomes.