title: Does radiation dose to the salivary glands and oral cavity predict patient-rated xerostomia and sticky saliva in head and neck cancer patients treated with curative radiotherapy?
abstract: OBJECTIVE
  To investigate the association between the mean salivary gland and oral cavity dose, with patient-rated moderate and severe xerostomia and sticky saliva.
  
  
  METHODS
  One hundred and fifty-seven patients treated with bilateral irradiation for head and neck cancer were included. The parotid and submandibular glands and the oral cavity were delineated on plannings-CT scans. At baseline and 6 and 12 months self-reported xerostomia and sticky saliva were assessed using the EORTC QLQ-H&N35 questionnaire.
  
  
  RESULTS
  At 6 months a significant association between the mean parotid (MD(par)) and mean submandibular dose (MD(subm)) and xerostomia was observed (OR - MD(par): 1.17; P=0.002 and OR - MD(subm): 1.08; P = 0.02). Between MD(par) and MD(subm), a significant interaction term was present. No significant association was found with the oral cavity dose. Xerostomia was reversible depending on MD(par) and MD(subm). Considering Sticky saliva, a significant association was found at 6 and 12 months with MD(subm) (OR: 1.03; P < 0.001). The P50 for sticky saliva increased with elapsing time.
  
  
  CONCLUSIONS
  Both MD(par) and MD(subm) influence the risk of xerostomia in irradiated patients at 6 months. This probability as a function of the mean parotid dose significantly depended on the mean dose in the submandibular glands. Sticky saliva mainly depends on MD(subm).
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. ap.jellema@vumc.nl
authors.forename: Anke Petra
authors.initials: AP
authors.lastname: Jellema
authors.forename: Patricia
authors.initials: P
authors.lastname: Doornaert
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Slotman
authors.forename: C Rene
authors.initials: CR
authors.lastname: Leemans
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Langendijk
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D016001:Confidence Intervals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000528:radiation effects; D015995:Prevalence; D011336:Probability; D011446:Prospective Studies; D011832:Radiation Injuries / Q000453:epidemiology; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D011882:Radiotherapy, High-Energy / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D012463:Saliva; D012469:Salivary Glands / Q000528:radiation effects*; D012472:Salivation / Q000528:radiation effects; D015996:Survival Rate; D016896:Treatment Outcome; D014987:Xerostomia / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology