Thoracic and Cranial Radiotherapy for Limited-Stage Small Cell Lung Cancer

¹ From the Joint Center for Radiation Therapy, Harvard Medical School, Boston

Chemotherapy remains the mainstay of treatment for small cell lung cancer (SCLC). For patients with limited-state disease, the addition of thoracic radiotherapy confers a moderate improvement in local control and a modest survival benefit, but these improvements come at the cost of increased toxic reactions. The optimal method for integrating chemotherapy and thoracic radiotherapy is unresolved. Concurrent and alternating strategies are appealing because they allow uninterrupted delivery of chemotherapy, but they have not been proven to be superior to conventional sequential approaches. Based on limited data, delivery of thoracic radiation early in the treatment course may be preferable to delivery later in the course. There is evidence of a radiation dose-response effect for SCLC, and, in standard regimens, thoracic radiation doses in the range of 50 to 60 Gy are recommended. The use of limited radiation fields (to postchemotherapy tumor volumes) appears reasonable. Results for alternative thoracic radiation fractionation schedules such as accelerated hyperfractionation are promising and worthy of further investigation. The role of prophylactic cranial irradiation (PCI) is controversial and should be individualized. It should be considered for the favorable subgroup of patients with limited-stage disease who achieve a complete response to chemotherapy and thoracic radiotherapy. If given, we recommend a total dose of 30 to 36 Gy in 2-Gy fractions; PCI should not be delivered concomitantly with chemotherapy.