Small Cell Lung Cancer

Small cell lung cancer accounts for approximately 15% of bronchogenic carcinomas. It is the cancer most commonly associated with various paraneoplastic syndromes, including the syndrome of inappropriate antidiuretic hormone secretion, paraneoplastic cerebellar degeneration, and Lambert-Eaton myasthenic syndrome. Because of the high propensity of small cell lung cancer to metastasize early, surgery has a limited role as primary therapy. Although the disease is highly sensitive to chemotherapy and radiation, cure is difficult to achieve. The combination of platinum and etoposide is the accepted standard chemotherapeutic regimen. It is also the accepted standard therapy in combination with thoracic radiotherapy (TRT) for limited-stage disease. Adding TRT increases absolute survival by approximately 5% over chemotherapy alone. Thoracic radiotherapy administered concurrently with chemotherapy is more efficacious than sequential therapy. Furthermore, the survival benefit is greater if TRT is given early rather than late in the course of chemotherapy. Regardless of disease stage, no relevant survival benefit results from increased chemotherapy dose intensity or dose density, altered mode of administration (eg, alternating or sequential administration) of various chemotherapeutic agents, or maintenance chemotherapy. Prophylactic cranial radiation prevents central nervous system recurrence and can improve survival. In Japan and some other Asian countries, the combination of irinotecan and cisplatin is the standard chemotherapeutic regimen. Clinical trials using thalidomide, gefitinib, imatinib, temsirolimus, and farnesyltransferase inhibitors have not shown clinical benefit. Other novel agents such as bevacizumab have shown promising early results and are being evaluated in larger trials.