title: Central versus Peripheral Tumor Location: Influence on Survival, Local Control, and Toxicity Following Stereotactic Body Radiotherapy for Primary Non-Small-Cell Lung Cancer.
abstract: BACKGROUND
  Stereotactic body radiotherapy (SBRT) has been increasingly utilized for medically inoperable early stage non-small-cell lung cancer. However, a lower biological equivalent dose (BED) is often used for central tumors given toxicity concerns, potentially leading to decreased local control (LC). We compared survival, LC, and toxicity outcomes for SBRT patients with centrally versus peripherally located tumors.
  
  
  METHODS
  We included patients with primary cT1-2N0M0 non-small-cell lung cancer treated with SBRT at our institution from September 2007 to August 2013 with follow-up through August 2014. Central tumor location was defined as within 2 cm of the proximal bronchial tree, heart, great vessels, trachea, or other mediastinal structures. Kaplan-Meier analysis and multivariable Cox regression modeling were used for overall survival (OS) and LC, and the χ test and multivariable logistic regression modeling were used for toxicity.
  
  
  RESULTS
  We included 251 patients (111 central, 140 peripheral) with median follow-up of 31.2 months. Patients with central tumors were more likely to be older (mean 75.8 versus 73.5 years; p = 0.04), have larger tumors (mean 2.5 cm versus 1.9 cm; p < 0.001), and be treated with a lower BED (mean 120.2 Gy versus 143.5 Gy; p < 0.001). Multivariable analysis revealed that tumor location was not associated with worse OS, LC, or toxicity. Patients with central tumors were less likely to have acute grade greater than or equal to three toxicity than those with peripheral tumors (odds ratio: 0.24; p = 0.02).
  
  
  CONCLUSIONS
  Central tumor location did not predict for inferior OS, LC, or toxicity following SBRT when a lower mean BED was utilized.
authors: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520. Electronic address: henry.park@yale.edu.
authors: Henry S
authors: HS
authors: Park
authors: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520.
authors: Eileen M
authors: EM
authors: Harder
authors: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520.
authors: Brandon R
authors: BR
authors: Mancini
authors: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520.
authors: Roy H
authors: RH
authors: Decker
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D004417:Dyspnea / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000401:mortality; D017564:Radiation Pneumonitis / Q000209:etiology*; D016634:Radiosurgery / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D047368:Tumor Burden