title: Olfactory bulb volume and olfactory function after radiotherapy in patients with nasopharyngeal cancer.
abstract: OBJECTIVE
  Radiotherapy is the primary method of treatment for nasopharyngeal cancer (NPC) and many side effects were reported in patients receiving radiation to this area. This study was conducted to evaluate the long-term effects of radiotherapy following NPC on olfactory bulb (OB) volume and olfactory function.
  
  
  METHODS
  Twenty-four patients with NPC who received radiotherapy at least 12 months ago were recruited. Fourteen healthy subjects with similar demographical characteristics were recruited as the healthy control group. All volunteers were subjected to a nasoendoscopical examination, and abnormalities that could potentially cause olfactory dysfunction were the exclusion criteria from the study. An experienced radiologist segmented the MRI coronal, axial and sagittal slices manually for three-dimensional OB volume measurement in a blinded manner. Olfactory function was assessed using the Connecticut Chemosensory Clinical Research Center (CCCRC) test, and average score (0: worst, 7: best) was calculated as the total CCCRC olfactory score.
  
  
  RESULTS
  The mean CCCRC score was 5.5 ± 1.1 for the nasopharyngeal cancer patients, whereas the mean score of healthy control group was 6.4 ± 0.4. There was a significant difference in the olfactory scores (p=0.003). The mean OB volume in the NPC group was 46.7 ± 12.1mm(3). Among the patients with NPC, the cisplatin receiving group had a mean OB volume of 47.2mm(3), whereas the cisplatin+docetaxel receiving group had a mean OB volume of 46.5mm(3), and they were similar. The MRI measurement of the healthy control group was 58.6 ± 13.8mm(3). The OB volumes of the healthy control group were significantly higher (p<0.05).
  
  
  CONCLUSIONS
  Radiotherapy following nasopharyngeal cancer results in a diminished OB volume and deteriorated olfactory function. Chemosensory olfactory dysfunction might be a contributing factor to lack of appetite, cancer cachexia and consequent lowered quality of life in NPC patients.
authors.affiliation: Bezmiâlem Vakif University, Medical Faculty, Department of Otolaryngology, Fatih, Istanbul, Turkey.
authors.forename: Bayram
authors.initials: B
authors.lastname: Veyseller
authors.affiliation: Bezmiâlem Vakif University, Medical Faculty, Department of Otolaryngology, Fatih, Istanbul, Turkey. Electronic address: berkeozucer@gmail.com.
authors.forename: Berke
authors.initials: B
authors.lastname: Ozucer
authors.affiliation: Bezmiâlem Vakif University, Medical Faculty, Department of Otolaryngology, Fatih, Istanbul, Turkey.
authors.forename: Nazan
authors.initials: N
authors.lastname: Degirmenci
authors.affiliation: Okmeydanı Research and Training Hospital, Department of Radiology, Istanbul, Turkey.
authors.forename: Defne
authors.initials: D
authors.lastname: Gurbuz
authors.affiliation: Istanbul University, Istanbul Medical Faculty, Department of Oncology, Çapa, Istanbul, Turkey.
authors.forename: Makbule
authors.initials: M
authors.lastname: Tambas
authors.affiliation: Istanbul University, Istanbul Medical Faculty, Department of Oncology, Çapa, Istanbul, Turkey.
authors.forename: Musa
authors.initials: M
authors.lastname: Altun
authors.affiliation: Bezmiâlem Vakif University, Medical Faculty, Department of Otolaryngology, Fatih, Istanbul, Turkey.
authors.forename: Fadullah
authors.initials: F
authors.lastname: Aksoy
authors.affiliation: Bezmiâlem Vakif University, Medical Faculty, Department of Otolaryngology, Fatih, Istanbul, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Ozturan
mesh_terms: D000328:Adult; D002277:Carcinoma; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D000857:Olfaction Disorders / Q000209:etiology* / Q000473:pathology; D009830:Olfactory Bulb / Q000473:pathology / Q000528:radiation effects*; D009929:Organ Size; D011788:Quality of Life; D011878:Radiotherapy / Q000009:adverse effects*; D012684:Sensory Thresholds; D012903:Smell / Q000528:radiation effects*
keywords: Dysosmia; Nasopharynx cancer; Olfactory bulbus; Olfactory dysfunction; Olfactory function; Radiotherapy; Smell