Small Cell Lung Cancer.

Small cell lung cancer (SCLC) is a high-grade neuroendocrine tumor characterized by rapid growth, early metastatic spread, and initial responsiveness to therapy. Although the incidence of SCLC is declining, it remains one of the common causes of cancer-related mortality. Initial evaluation of patients with SCLC should focus on determining the extent of disease and the ability of the patient to tolerate specific therapy. Positron emission tomography (PET) can improve the accuracy of staging and treatment planning in many patients. Limited-stage (LS) SCLC is a potentially curable disease with long-term survival of 20 to 25% when treated with platinum-based chemotherapy plus concurrent thoracic radiation. Hyperfractionated (twice daily) thoracic radiation and prophylactic cranial irradiation (PCI) may improve survival in selected patients with LS-SCLC. For patients with extensive-stage (ES) SCLC, combination chemotherapy prolongs survival and improves quality of life, but long-term survival is rare. The use of PCI and sequential thoracic radiation has been reported to improve survival in selected patients with ES-SCLC. Many chemotherapeutic drugs have activity in SCLC, but little progress has been made in the systemic treatment of SCLC in almost three decades. Although many potential molecular targets have been identified in the preclinical studies of SCLC, molecularly targeted therapy has yet to demonstrate consistent clinical activity. Nevertheless, future advances in SCLC will depend on the development of rational therapeutic strategies which target the molecular mechanisms that drive cellular proliferation, survival, and immunological avoidance.