title: A systematic review of smell alterations after radiotherapy for head and neck cancer.
abstract: OBJECTIVE
  To review the current knowledge on radiotherapy associated olfactory dysfunction among head and neck cancer (HNC) patients.
  
  
  METHODS
  A systematic review of RT-related olfactory dysfunction in HNC was performed. Searches were conducted in several databases (Medline, EMBASE, CINAHL, CAB Abstracts, SCOPUS, Proquest Dissertations and Theses, PROSPERO, ALLEBM Reviews - Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, and NHSEED). Publications investigating olfactory dysfunction as an explicit side effect of Radiotherapy (RT, or RT-chemo or RT-monoclonal antibodies) were eligible, no limits were applied.
  
  
  RESULTS
  Two hundred and twenty-nine papers were screened and 23 met inclusion criteria.
  
  
  CONCLUSIONS
  Odor detection, identification and discrimination are olfactory functions impaired after RT for HNC. An RT dose-effect has been calculated for odor identification and odor discrimination. There were no studies of the effect of olfactory dysfunction on weight loss or energy intake among RT-treated HNC patients. To improve our understanding of RT associated olfactory dysfunction among HNC patients, future studies should include a multi-dimensional assessment of olfactory function in a longitudinal design, track other conditions affecting olfaction, assess retronasal olfactory perception, adopt validated self-report tools and explore the impact of olfactory dysfunction on the eating experience of HNC patients.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Álvarez-Camacho
authors.affiliation: Dipartimento di Scienze della Sanità Pubblica e Pediatriche, Università degli Studi di Torino, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Gonella
authors.affiliation: John W. Scott Health Sciences Library, University of Alberta, Edmonton, AB, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Campbell
authors.affiliation: Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Scrimger
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada. Electronic address: wwismer@ualberta.ca.
authors.forename: W V
authors.initials: WV
authors.lastname: Wismer
mesh_terms: D004307:Dose-Response Relationship, Radiation; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D000857:Olfaction Disorders / Q000209:etiology*; D011878:Radiotherapy / Q000009:adverse effects*
keywords: Head and neck cancer; Odor detection; Odor discrimination; Odor recognition; Olfaction; Olfactory dysfunction; Radiotherapy; Smell alterations