Prophylactic cranial irradiation in the treatment of small-cell carcinoma of the lung.

The high incidence of central nervous system (CNS) failure in patients given chemotherapy for small-cell lung cancer led to the use of prophylactic cranial irradiation (PCI) to prevent the development of metastases. Seven randomized trials have investigated the use of PCI, 5 of which reported a statistically significant reduction in risk of CNS disease though none demonstrated improvement in overall survival. Recent reports have demonstrated the potential for severe toxicity with PCI, leading some investigators to recommend discontinuing its use, while others have suggested improvements in timing and dose fractionation. It appears that the subgroup of patients most likely to benefit from PCI are those with limited-stage disease in complete response after chemotherapy, in whom a reduction in the risk of CNS failure may translate into improved survival. The recommended radiation dose is 30 to 36 Gy in 2 Gy/day fractions.