title: [Parotid dysfunction after various methods of radiotherapy for nasopharyngeal carcinoma].
abstract: OBJECTIVE
  To evaluate the radiation induced parotid dysfunction in nasopharyngeal carcinoma (NPC) patients who had received different methods of radiotherapy.
  
  
  METHODS
  From January 1996 to January 2000, 380 NPC patients were divided into conventional fraction (CF-175 patients), late-course accelerated hyperfractionation (LCAF-63 patients) and intensity modulated radiation therapy (IMRT-142 patients) groups. Conventional radiotherapy was given with a total dose of 70 Gy. Patients in the LCAF group were treated with the same fractionation as CF group until the dose of 36 - 40 Gy, then followed by LCAF radiotherapy to a total dose of 75 Gy. IMRT in the form of full-course was given to a total dose of 72 Gy. Acute parotiditis was observed during the treatment. The parotid secretory function was examined 2 years after radiotherapy.
  
  
  RESULTS
  The dose of parotid in IMRT was much lower than those in the other 2 groups. Extreme damage rates of parotid secretory function in CF, LCAF and IMRT groups were 81.7%, 81.0% and 69.7% (P < 0.05); acute parotiditis rates were 23.4%, 20.4% and 41.3% respectively, with the differences among the 3 groups significant (P < 0.05).
  
  
  CONCLUSIONS
  The radiation parotid functional damage differs in the various methods of radiotherapy. IMRT, being able to improve the tumor target coverage and spare the adjacent critical structures, is indicated for NPC.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Guangdong Provincial Second Hospital, Guangzhou 510317, China. wu-yang177@126.com
authors.forename: Yang
authors.initials: Y
authors.lastname: Wu
authors.forename: Sui-bao
authors.initials: SB
authors.lastname: Chen
authors.forename: Chang-qing
authors.initials: CQ
authors.lastname: Cai
mesh_terms: D000293:Adolescent; D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D010306:Parotid Gland / Q000503:physiopathology / Q000528:radiation effects*; D010309:Parotitis / Q000209:etiology; D011832:Radiation Injuries / Q000503:physiopathology*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*