title: Intensity-modulated radiation therapy in oropharyngeal carcinoma: effect of tumor volume on clinical outcomes.
abstract: OBJECTIVE
  To analyze the effect of primary gross tumor volume (pGTV) and nodal gross tumor volume (nGTV) on treatment outcomes in patients treated with definitive intensity-modulated radiation therapy (IMRT) for oropharyngeal cancer (OPC).
  
  
  METHODS
  Between September 1998 and April 2009, a total of 442 patients with squamous cell carcinoma of the oropharynx were treated with IMRT with curative intent at our center. Thirty patients treated postoperatively and 2 additional patients who started treatment more than 6 months after diagnosis were excluded. A total of 340 patients with restorable treatment plans were included in this present study. The majority of the patients underwent concurrent platinum-based chemotherapy. The pGTV and nGTV were calculated using the original clinical treatment plans. Cox proportional hazards models and log-rank tests were used to evaluate the correlation between tumor volumes and overall survival (OS), and competing risks analysis tools were used to evaluate the correlation between local failure (LF), regional failure (RF), distant metastatic failure (DMF) vs. tumor volumes with death as a competing risk.
  
  
  RESULTS
  Median follow-up among surviving patients was 34 months (range, 5-67). The 2-year cumulative incidence of LF, RF and DF in this cohort of patients was 6.1%, 5.2%, and 12.2%, respectively. The 2-year OS rate was 88.6%. Univariate analysis determined pGTV and T-stage correlated with LF (p < 0.0001 and p = 0.004, respectively), whereas nGTV was not associated with RF. On multivariate analysis, pGTV and N-stage were independent risk factors for overall survival (p = 0.0003 and p = 0.0073, respectively) and distant control (p = 0.0008 and p = 0.002, respectively).
  
  
  CONCLUSIONS
  In this cohort of patients with OPC treated with IMRT, pGTV was found to be associated with overall survival, local failure, and distant metastatic failure.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Lok
authors.forename: Jeremy
authors.initials: J
authors.lastname: Setton
authors.forename: Nicola
authors.initials: N
authors.lastname: Caria
authors.forename: Jonathan
authors.initials: J
authors.lastname: Romanyshyn
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: Wolden
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
authors.forename: Jeffery
authors.initials: J
authors.lastname: Park
authors.forename: Nicholas
authors.initials: N
authors.lastname: Rowan
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Sherman
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Fury
authors.forename: Alan
authors.initials: A
authors.lastname: Ho
authors.forename: David G
authors.initials: DG
authors.lastname: Pfister
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Wong
authors.forename: Jatin P
authors.initials: JP
authors.lastname: Shah
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Kraus
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Karen D
authors.initials: KD
authors.lastname: Schupak
authors.forename: Daphna Y
authors.initials: DY
authors.lastname: Gelblum
authors.forename: Shyam D
authors.initials: SD
authors.lastname: Rao
authors.forename: Nancy Y
authors.initials: NY
authors.lastname: Lee
mesh_terms: D000704:Analysis of Variance; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D009959:Oropharyngeal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D016016:Proportional Hazards Models; D050397:Radiotherapy, Intensity-Modulated / Q000401:mortality; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D000970:Antineoplastic Agents