Prophylactic cranial irradiation in patients with extensive disease caused by small-cell lung cancer responsive to chemotherapy: fewer symptomatic brain metastases and improved survival

OBJECTIVE: To determine the effect of prophylactic cranial irradiation (PCI) in patients with extensive-disease small-cell lung cancer (ED-SCLC) who responded to chemotherapy. DESIGN: Randomised, controlled clinical trial; phase III study (EORTC nr 08993-22993; www.clinicaltrials.gov, nr NCT00016211). METHOD: Patients aged 18-75 years with a functional status according to WHO < or = 2, and with ED-SCLC and any response to chemotherapy, were randomized to observation (standard care) or PCI. The primary endpoint was time to symptomatic brain metastases. If any pre-defined, key symptom suggesting brain metastases presented, a CT or MRI scan of the brain was performed. The size of the study (143 patients per arm) was determined to detect a hazard ratio (HR) of 0.44 at 80% power with 2-sided alpha = 0.05. RESULTS: The study accrued 286 patients. PCI decreased the risk of developing symptomatic brain metastases (HR = 0.27 (95% CI: 0.16-0.44; p < 0.001)). The cumulative incidence of developing brain metastases within 1 year was 40% in the control group (95% CI: 32-49) and 15% in the PCI group (95% CI: 8-21). PCI prolonged disease-free (HR = 0.76; 95% CI: 0.59-0.96, p = 0.02) and overall survival (HR = 0.68; 95% CI; 0.52-0.88, p = 0.003). The 1-year survival rate was 27% (95% CI: 19-36) for the PCI group versus 13% (95% CI: 8-20) for controls. Acute and late treatment toxicity was acceptable. These side effects did not significantly impact on quality of life. CONCLUSIONS: PCI significantly reduced the incidence of symptomatic brain metastases and prolonged both disease-free and overall survival and should be part of standard care in SCLC patients who respond to chemotherapy.