[Prophylactic cranial irradiation in small cell lung cancer]

The Brain is one of the common relapse sites in small cell lung cancer because of isolation from chemotherapeutic agents by the blood-brain barrier. Prophylactic cranial irradiation (PCI) is expected to reduce brain relapse and increase the survival rate. PCI prolonged the survival in only 10-20% of patients with small cell lung cancer after complete response. Most randomized trials demonstrated the significant reduction of brain relapse, however, none of them demonstrated an increase of survival rate because their sample sizes were relatively small to detect the difference of survival, such as 10% in 3-year survival. The results of ongoing meta-analysis should provide new findings on the survival benefits of PCI. No standard PCI dose and schedule are established, however, over 30Gy for total dose, over 3Gy per fraction. Concurrent use with chemotherapy is considered to induce central nerve toxicity. PCI should be proposed for patients with complete response as an optional treatment.