Radiotherapy in small-cell lung cancer: where should it go?

Small-cell lung carcinomas (SCLC) represent less than 20% of all lung cancers. As it is an aggressive tumour, on account of its high and early risk of dissemination, only a third of patients have limited-stage disease at diagnosis. For these patients, the current state-of-the-art treatment involves cisplatin-etoposide chemotherapy combined with chest radiotherapy. Because of the high risk of brain metastases, prophylactic cranial irradiation (PCI) is indicated in good responders and should be part of the standard management of these patients on the basis of a PCI meta-analysis showing a 5% increase in survival at 3 years. The 5-year survival rate reaches 25% in the best series. This progress is subsequent to a better combination of polychemotherapy and both thoracic and cerebral irradiation. In extensive disease, radiotherapy has also a place in the management of SCLC: PCI reduces the risk of brain metastases and significantly improves overall survival, so that cisplatin (or carboplatin)-etoposide followed by PCI in responding patients has become the standard treatment. Many issues are subject for further clinical research concerning timing, volume and schedule of thoracic radiotherapy to be used in combination with chemotherapy regimen. Progress in thoracic radiotherapy can only be achieved by including patients in prospective studies.