title: Prognostic impact of radiation therapy to the primary tumor in patients with non-small cell lung cancer and oligometastasis at diagnosis.
abstract: OBJECTIVE
  We investigated prognostic factors associated with survival in patients with non-small cell lung cancer (NSCLC) and oligometastatic disease at diagnosis, particularly the influence of local treatment to the primary site on prognosis.
  
  
  METHODS
  From January 2000 through June 2011, 78 consecutive patients with oligometastatic NSCLC (<5 metastases) at diagnosis underwent definitive chemoradiation therapy (≥45 Gy) to the primary site. Forty-four of these patients also received definitive local treatment for the oligometastases. Survival outcomes were estimated using the Kaplan-Meier method, and risk factors were identified by univariate and multivariate analyses.
  
  
  RESULTS
  Univariate Cox proportional hazard analysis revealed better overall survival (OS) for those patients who received at least 63 Gy of radiation to the primary site (P=.002), received definitive local treatment for oligometastasis (P=.041), had a Karnofsky performance status (KPS) score >80 (P=.007), had a gross tumor volume ≤124 cm³ (P=.002), had adenocarcinoma histology (P=.002), or had no history of respiratory disease (P=.016). On multivariate analysis, radiation dose, performance status, and tumor volume retained significance (P=.004, P=.006, and P<.001, respectively). The radiation dose also maintained significance when patients with and without brain metastases were analyzed separately.
  
  
  CONCLUSIONS
  Tumor volume, KPS, and receipt of at least 63 Gy to the primary tumor are associated with improved OS in patients with oligometastatic NSCLC at diagnosis. Our results suggest that a subset of such patients may benefit from definitive local therapy.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Lopez Guerra
authors.forename: Daniel
authors.initials: D
authors.lastname: Gomez
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuang
authors.forename: David S
authors.initials: DS
authors.lastname: Hong
authors.forename: John V
authors.initials: JV
authors.lastname: Heymach
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Swisher
authors.forename: Steven H
authors.initials: SH
authors.lastname: Lin
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liao
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011879:Radiotherapy Dosage; D012307:Risk Factors; D047368:Tumor Burden