title: Salivary Anionic Changes after Radiotherapy for Nasopharyngeal Carcinoma: A 1-Year Prospective Study.
abstract: OBJECTIVE
  To investigate the salivary anionic changes of patients with nasopharyngeal carcinoma (NPC) treated by radiotherapy.
  
  
  METHODS
  Thirty-eight patients with T1-4, N0-2, M0 NPC received conventional radiotherapy. Stimulated whole saliva was collected at baseline and 2, 6 and 12 months after radiotherapy. Salivary anions levels were measured using ion chromatography.
  
  
  RESULTS
  A reduction in stimulated saliva flow and salivary pH was accompanied by sustained changes in anionic composition. At 2 months following radiotherapy, there was a significant increase in chloride, sulphate, lactate and formate levels while significant reductions in nitrate and thiocyanate levels were found. No further changes in these anion levels were observed at 6 and 12 months. No significant changes were found in phosphate, acetate, or propionate levels throughout the study period.
  
  
  CONCLUSIONS
  Conventional radiotherapy has a significant and prolonged impact on certain anionic species, likely contributing to increased cariogenic properties and reduced antimicrobial capacities of saliva in NPC patients post-radiotherapy.
authors.affiliation: Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Edmond H N
authors.initials: EH
authors.lastname: Pow
authors.affiliation: Department of Oral Implantology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.
authors.forename: Zhuofan
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Dora L W
authors.initials: DL
authors.lastname: Kwong
authors.affiliation: Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Otto L T
authors.initials: OL
authors.lastname: Lam
mesh_terms: D000085:Acetates / Q000032:analysis; D000328:Adult; D000368:Aged; D000838:Anions / Q000032:analysis*; D002277:Carcinoma; D002712:Chlorides / Q000032:analysis; D005260:Female; D005561:Formates / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000032:analysis; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D009305:Nasopharynx / Q000473:pathology* / Q000528:radiation effects; D010710:Phosphates / Q000032:analysis; D011446:Prospective Studies; D012463:Saliva / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis
chemical_list: D000085:Acetates; D000838:Anions; D002712:Chlorides; D005561:Formates; D010710:Phosphates; D013431:Sulfates; C030544:formic acid; D019344:Lactic Acid