title: Clinical characteristics and patterns of failure in the parotid region after intensity-modulated radiotherapy for nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To discuss the clinical characteristics and patterns of failure in the parotid region after intensity-modulated radiotherapy for nasopharygeal carcinoma.
  
  
  METHODS
  We retrospectively reviewed the charts of 716 patients with nasopharygeal carcinoma who underwent intensity-modulated radiotherapy in our centre from January 2005 to December 2010. Disease recurred in a spared parotid gland in 10 patients (1.4%). There were 2 females and 8 males with a median age of 38.5 (34-53) years. The most common presenting symptom was a swelling in pre-auricular region (7/10). Parotid glands were spared bilaterally in these patients. None of these patients had undergone previous radiotherapy or surgical treatment of the head and neck. The location of periparotid failures were transferred to the pretreatment planning computed tomography for dosimetry analysis.
  
  
  RESULTS
  The median time from day 1 of radiotherapy to periparoid recurrence was 17.4 (4.4-40.5) months. The median survivial after periparoid recurrence was 25.1 (5.0-74.5) months. There were 9 (90%) patients with lateral retropharyngeal lymphadenopathy. Seven of the periparotid failures were marginal. Of the 7 marginal failures, 6 occurred at the ipslateral parotid of the primary tumor centre. The average mean dose of the ipslateral parotid was 38.1 (32.3-44.1) Gy.
  
  
  CONCLUSIONS
  Periparotid recurrence is an uncommon pattern of failure after definitive intensity-modulated radiotherapy for nasopharygeal carcinoma. To reduce the risk of periparotid recurrence,one possible strategy is to lessen the dose constraint criteria to ipslateral parotid of the primary tumor centre especially for nasopharygeal carcinoma with lateral retropharyngeal lymphadenopathy.
authors: Department of Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors: Cai-neng
authors: CN
authors: Cao
authors: Jing-wei
authors: JW
authors: Luo
authors: Li
authors: L
authors: Gao
authors: Jun-lin
authors: JL
authors: Yi
authors: Xiao-dong
authors: XD
authors: Huang
authors: Kai
authors: K
authors: Wang
authors: Shi-ping
authors: SP
authors: Zhang
authors: Yuan
authors: Y
authors: Qu
authors: Su-yan
authors: SY
authors: Li
authors: Wei-ming
authors: WM
authors: Cai
authors: Jian-ping
authors: JP
authors: Xiao
authors: Zhong
authors: Z
authors: Zhang
authors: Guo-zhen
authors: GZ
authors: Xu
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D010306:Parotid Gland / Q000473:pathology / Q000528:radiation effects*; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies