title: Scintigraphic assessment of salivary function after intensity-modulated radiotherapy for head and neck cancer: correlations with parotid dose and quality of life.
abstract: OBJECTIVE
  We investigated salivary function using quantitative scintigraphy and sought to identify functional correlations between parotid dose and quality of life (QoL) for head and neck cancer (HNC) patients receiving intensity-modulated radiotherapy (IMRT).
  
  
  METHODS
  Between August, 2007 and June, 2008, 31 patients treated IMRT for HNC were enrolled in this prospective study. Salivary excretion function (SEF) was previously measured by salivary scintigraphy at annual intervals for 2 years after IMRT. A dose-volume histogram of each parotid gland was calculated, and the normal tissue complication probability (NTCP) was used to determine the tolerance dose. QoL was longitudinally assessed by the EORTC QLQ-C30 and H&N35 questionnaires prior to RT, and at one, three, 12 and 24 months after RT.
  
  
  RESULTS
  A significant correlation was found between the reduction of SEF and the mean parotid dose measured at 1 year (correlation coefficient, R(2)=0.651) and 2 years (R(2)=0.310) after IMRT (p<0.001). The TD(50) of the parotid gland at 1 year after IMRT is 43.6 Gy, comparable to results from western countries. We further found that contralateral parotid and submandibular gland function preservation was correlated with reduced sticky saliva and a better QoL compared to the functional preservation of both parotid glands, as determined by the EORTC QLQ-H&N35 questionnaire.
  
  
  CONCLUSIONS
  A significant correlation was found between the reduction of SEF and the mean parotid dose. Preservation of contralateral parotid and submandibular gland function predicts a better QoL compared to preservation of the function of both parotid glands.
authors.affiliation: Department of Radiation Oncology, Chang Gung Memorial Hospital, Chiayi, and Chang Gung University, College of Medicine, Tao-yuan, Taiwan.
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Chen
authors.forename: Chia-Hsuan
authors.initials: CH
authors.lastname: Lai
authors.forename: Tsair-Fwu
authors.initials: TF
authors.lastname: Lee
authors.forename: Chao-Hsiung
authors.initials: CH
authors.lastname: Hung
authors.forename: Kuo-Chi
authors.initials: KC
authors.lastname: Liu
authors.forename: Ming-Fong
authors.initials: MF
authors.lastname: Tsai
authors.forename: Wen-Hung
authors.initials: WH
authors.lastname: Wang
authors.forename: Hungcheng
authors.initials: H
authors.lastname: Chen
authors.forename: Fu-Ming
authors.initials: FM
authors.lastname: Fang
authors.forename: Miao-Fen
authors.initials: MF
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D010306:Parotid Gland / Q000000981:diagnostic imaging / Q000378:metabolism / Q000528:radiation effects*; D011446:Prospective Studies; D011788:Quality of Life; D011877:Radionuclide Imaging; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D020127:Recovery of Function / Q000528:radiation effects; D012463:Saliva / Q000378:metabolism / Q000528:radiation effects*; D013363:Submandibular Gland / Q000000981:diagnostic imaging / Q000378:metabolism / Q000528:radiation effects; D014987:Xerostomia / Q000000981:diagnostic imaging / Q000209:etiology