title: Prophylactic cranial irradiation after definitive chemoradiotherapy for limited-stage small cell lung cancer: Do all patients benefit?
abstract: Prophylactic cranial irradiation (PCI) can improve overall survival (OS) and suppress brain metastases (BM) in patients with limited-stage small cell lung cancer (LS-SCLC) after complete response to primary therapy. However, PCI can be toxic. We sought to identify characteristics of patients who may not benefit from PCI.
  
  
  
  We identified 658 patients who received chemoradiotherapy at MD Anderson in 1986-2012; 364 received PCI and 294 did not. Median follow-up time was 21.2months (range 1.2-240.8months). Cox proportional hazards regression, competing-risk regression, and Kaplan-Meier analyses were used to identify factors influencing OS and BM.
  
  
  
  PCI reduced risks of death [HR 0.73, 95% CI 0.61-0.88, P=0.001] and BM [HR 0.54, 95% CI 0.39-0.76, P<0.001]. Having tumors ⩾5cm increased the risk of BM [HR 1.77, 95% CI 1.22-2.55, P=0.002] but not death [HR 1.16, 95% CI 0.96-1.40, P=0.114]. Among patients ⩾70years with ⩾5-cm tumors, PCI did not improve OS [2-year rates 39.4% vs 40.9%, P=0.739].
  
  
  
  PCI remains standard therapy after complete response to chemoradiotherapy for LS-SCLC. However, older patients may be at risk from comorbidity or extracranial disease. Further work is warranted to identify patients who may not benefit from PCI.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
authors.forename: Ahsan S
authors.initials: AS
authors.lastname: Farooqi
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
authors.forename: Emma B
authors.initials: EB
authors.lastname: Holliday
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Allen
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
authors.forename: Xiong
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States. Electronic address: rkomaki@mdanderson.org.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000517:prevention & control / Q000556:secondary*; D059248:Chemoradiotherapy; D016371:Cranial Irradiation / Q000009:adverse effects; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*
keywords: Chemoradiation; Elderly patients; Overall survival; Prognostic factors; Prophylactic cranial irradiation; Small cell lung cancer