Effect of Prophylactic Cranial Irradiation on Survival in Elderly Patients With Limited-Stage Small Cell Lung Cancer

BACKGROUNDProphylactic cranial irradiation (PCI) improves survival in patients with limited-stage small cell lung cancer (SCLC) who have a complete response to chemotherapy and radiotherapy, yet to the best of the authors' knowledge, data specific to the elderly population are lacking. METHODSUsing the Surveillance, Epidemiology, and End Results (SEER) database, the authors identified 1926 patients aged70 years who were diagnosed with limited-stage SCLC between 1988 and 1997. Overall survival (OS) for patients who received PCI versus those who did not were estimated using the Kaplan-Meier method and compared with the log-rank test. A Cox proportional hazards model was further fitted to estimate the effect of PCI on OS after adjusting for age, race, sex, tumor size, lymph node status, stage of disease, and receipt of thoracic radiotherapy and surgery. RESULTSThe median age of the patients was 75 years (range, 70 years-94 years) and 138 patients (7.2 %) received PCI. The 2-year and 5-year OS rates were 33.3% (95% confidence interval [95% CI], 25.6%-41.2%) and 11.6% (95% CI, 6.9%-17.6%), respectively, among patients who received PCI versus 23.1% (95% CI, 21.2%-25.1%) and 8.6% (95% CI, 7.3%-9.9%), respectively, among patients who did not receive PCI (P=.028). On multivariable analysis, PCI was found to be an independent predictor of OS (hazards ratio, 0.72; 95% CI, 0.54-0.97 [P=.032]). On subgroup analysis, PCI remained an independent predictor of OS among patients aged75 years, but not among patients aged80 years. CONCLUSIONSThe receipt of PCI is associated with improved OS in patients aged 70 years with SCLC, suggesting that the benefit of PCI is maintained in the elderly population. Cancer 2013;119:3753-3760. (c) 2013 American Cancer Society.