title: Brain Metastases at Presentation in Patients With Non-Small Cell Lung Cancer.
abstract: OBJECTIVE
  We used brain radiotherapy as a surrogate for the presence of brain metastases in patients with non-small cell lung cancer (NSCLC) to determine the prevalence of brain metastases using the Surveillance Epidemiology and End Results database.
  
  
  METHODS
  Patients with NSCLC diagnosed between 1988 and 1997 were subdivided according to brain radiotherapy status at presentation into: "none" or "radiation therapy indicated." We calculated the frequency of brain radiotherapy use in all patients. Odds ratios (ORs) for the indication of brain radiotherapy were calculated for individual prespecified covariates of interest. All statistical tests were 2-sided and P<0.05 were considered significant.
  
  
  RESULTS
  At presentation, brain radiotherapy was indicated in 10,963 (8.3%) of the 131,456 patients diagnosed with NSCLC between 1988 and 1997. On multivariable analysis the following were significantly associated with brain radiotherapy use: age (OR, 0.653 per 10 y increase in age; 95% confidence interval [CI]: 0.642, 0.665); female sex (OR, 1.05; 95% CI: 1.01, 1.10]); adenocarcinoma histology (HR, 1.67; 95% CI: 1.58, 1.76) or large cell or other histology (OR, 1.67; 95% CI: 1.57, 1.77); tumor size>3 cm (3.1 to 5 cm OR, 1.22; 95% CI: 1.14, 1.30 and >5 cm OR, 1.25; 95% CI: 1.17, 1.33); tumor grade >II (grade III OR, 1.82; 95% CI: 1.69, 1.95 and grade IV OR, 1.91; 95% CI: 1.73, 2.11); and nodal involvement N1 (OR, 1.33; 95% CI: 1.20, 1.47), N2 (OR, 2.24; 95% CI: 2.10, 2.40), and N3 (OR, 2.39; 95% CI: 2.19, 2.60).
  
  
  CONCLUSIONS
  Brain radiotherapy is indicated in over 8% of patients with NSCLC at presentation. We demonstrated that the risk of brain metastasis at presentation may be stratified with the use of 6 clinical factors.
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology.
authors.forename: Saiama N
authors.initials: SN
authors.lastname: Waqar
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology.
authors.forename: Sadaf H
authors.initials: SH
authors.lastname: Waqar
authors.affiliation: Division of Biostatistics.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Trinkaus
authors.affiliation: Southwest Cancer Center, Orlando, FL.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Gadea
authors.affiliation: Departments of Radiation Oncology.
authors.forename: Cliff G
authors.initials: CG
authors.lastname: Robinson
authors.affiliation: Departments of Radiation Oncology.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Bradley
authors.affiliation: Pathology and Immunology.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Watson
authors.affiliation: Surgery, Washington University School of Medicine, St. Louis, MO.
authors.forename: Varun
authors.initials: V
authors.lastname: Puri
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology.
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Govindan
authors.affiliation: Department of Internal Medicine, Division of Medical Oncology.
authors.forename: Daniel
authors.initials: D
authors.lastname: Morgensztern
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D001932:Brain Neoplasms / Q000453:epidemiology / Q000532:radiotherapy* / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000453:epidemiology / Q000556:secondary* / Q000628:therapy; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012372:ROC Curve; D011879:Radiotherapy Dosage; D012042:Registries; D018570:Risk Assessment; D018426:SEER Program; D016019:Survival Analysis; D016896:Treatment Outcome