title: Margin on gross tumor volume and risk of local recurrence in head-and-neck cancer.
abstract: OBJECTIVE
  To determine whether the method or extent of construction of the high-dose clinical target volume (CTV) and high-dose planning target volume (PTV) in intensity-modulated radiation therapy (IMRT) for head-and-neck cancer are associated with an increased risk of locoregional failure.
  
  
  METHODS
  Patients with nasopharyngeal, oropharyngeal, oral cavity, hypopharyngeal, or laryngeal squamous cell carcinomas treated definitively with IMRT were included. All patients without local relapse had a minimum follow-up of 12 months. Median follow-up for all patients was 24 months. Treatment plans of 85 available patients were reviewed, and the gross tumor volume (GTV) to PTV expansion method was estimated.
  
  
  RESULTS
  The GTVs were expanded volumetrically in 71 of 85 patients, by a median of 15 mm (range, 4-25 mm). An anatomic component to the expansion of GTV was used in 14 of 85 patients. Eighteen patients failed locoregionally, for an actuarial locoregional control rate of 77.2% at 2 years. There was no significant difference in locoregional control between patients with GTVs expanded volumetrically vs. those with a component of anatomic expansion. In patients with GTVs expanded volumetrically, no increase in risk of local failure was seen in patients with a total GTV expansion of < or =15 mm.
  
  
  CONCLUSIONS
  In this retrospective study, there was not an increased risk of local failure using smaller margins or expanding GTVs volumetrically when treating head-and-neck cancer patients definitively with IMRT.
authors.affiliation: Department of Radiation Oncology, University of Alabama-Birmingham, Birmingham, AL 35249, USA.
authors.forename: Jimmy J
authors.initials: JJ
authors.lastname: Caudell
authors.forename: Ruby F
authors.initials: RF
authors.lastname: Meredith
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Spencer
authors.forename: Kimberley S
authors.initials: KS
authors.lastname: Keene
authors.forename: M Christian
authors.initials: MC
authors.lastname: Dobelbower
authors.forename: James A
authors.initials: JA
authors.lastname: Bonner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology / Q000532:radiotherapy; D009364:Neoplasm Recurrence, Local; D010610:Pharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy; D017410:Practice Guidelines as Topic; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D017211:Treatment Failure; D047368:Tumor Burden