title: Improved survival using intensity-modulated radiation therapy in head and neck cancers: a SEER-Medicare analysis.
abstract: BACKGROUND
  Intensity-modulated radiation therapy (IMRT) is a technologically advanced, and more expensive, method of delivering radiation therapy with a goal of minimizing toxicity. It has been widely adopted for head and neck cancers; however, its comparative impact on cancer control and survival remains unknown. The goal of this analysis was to compare the cause-specific survival (CSS) for patients with head and neck cancers treated with IMRT versus non-IMRT from 1999 to 2007.
  
  
  METHODS
  CSS was determined using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database and analyzed regarding treatment details, including the use of IMRT versus non-IMRT, using claims data. Hazard ratios (HRs) were estimated by the frailty model with a propensity score matching cohort and instrumental variable analysis.
  
  
  RESULTS
  A total of 3172 patients were identified. With a median follow-up of 40 months, patients treated with IMRT had a statistically significant improvement in CSS compared with those treated with non-IMRT (84.1% versus 66.0%; P < .001). When each anatomic subsite was analyzed separately, all respective subgroups of patients treated with IMRT had better CSS than those treated with non-IMRT. In multivariable survival analyses, patients treated with IMRT were associated with better CSS (HR = 0.72, 95% confidence interval = 0.59 to 0.90 for propensity score matching; HR = 0.60, 95% confidence interval = 0.41 to 0.88 for instrumental variable analysis).
  
  
  CONCLUSIONS
  Patients with head and neck cancers who were treated with IMRT experienced significant improvements in CSS compared with patients treated with non-IMRT techniques. This suggests there may be benefits to IMRT in cancer outcomes, in addition to toxicity reduction, for this patient population.
authors.affiliation: Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Beth M
authors.initials: BM
authors.lastname: Beadle
authors.forename: Kai-Ping
authors.initials: KP
authors.lastname: Liao
authors.forename: Linda S
authors.initials: LS
authors.lastname: Elting
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Buchholz
authors.forename: K Kian
authors.initials: KK
authors.lastname: Ang
authors.forename: Adam S
authors.initials: AS
authors.lastname: Garden
authors.forename: B Ashleigh
authors.initials: BA
authors.lastname: Guadagnolo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000532:radiotherapy*; D015331:Cohort Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality* / Q000532:radiotherapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D006278:Medicare; D057216:Propensity Score; D050397:Radiotherapy, Intensity-Modulated; D018426:SEER Program; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
keywords: SEER-Medicare; head and neck cancer; intensity-modulated radiation therapy; oropharynx cancer; radiation oncology