title: External auditory canal cholesteatoma in patients given radiotherapy for nasopharyngeal carcinoma.
abstract: BACKGROUND
  Patients who undergo radiotherapy (RT) for nasopharyngeal carcinoma (NPC) may develop external auditory canal cholesteatoma (EACC).
  
  
  METHODS
  The records of patients with newly diagnosed NPC who had received concomitant chemotherapy and RT in a tertiary referral center from 1997 January to 2012 July were retrospectively reviewed.
  
  
  RESULTS
  RT-related external auditory canal cholesteatoma (RT-related EACC) was identified in 15 of 833 patients given RT for NPC. Three patients had EACC in both ears. The interval from completion of RT to the diagnosis of EACC ranged from 0.5 to 15.4 years (mean, 5.6 years). RT-related EACC commonly (75%) invaded the anterior and inferior parts of the external canal wall. Canaloplasty was used in 12 patients to surgically remove cholesteatoma. There was no recurrence of RT-related EACC during the study period.
  
  
  CONCLUSIONS
  Patients with NPC might contract RT-related EACC a few years after RT. We hypothesize that a fraction dose of 200 cGy or more induces RT-related EACC.
authors.affiliation: Department of Otolaryngology, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Shiou-Shyan
authors.initials: SS
authors.lastname: Yu
authors.affiliation: Department of Otolaryngology, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Kuan-Ji
authors.initials: KJ
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology, Chi Mei Medical Center, Tainan, Taiwan.|Center of General Education, Southern Taiwan University of Science and Technology, Taipei, Taiwan.
authors.forename: Yung-Song
authors.identifier: http://orcid.org/0000-0002-2758-5163
authors.initials: YS
authors.lastname: Lin
mesh_terms: D000046:Academic Medical Centers; D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D059186:Chemoradiotherapy, Adjuvant / Q000009:adverse effects / Q000379:methods; D002781:Cholesteatoma / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D004424:Ear Canal; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000628:therapy*; D009367:Neoplasm Staging; D012189:Retrospective Studies; D013524:Surgical Flaps; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
keywords: canaloplasty; external auditory canal cholesteatoma; head and neck cancer; nasopharyngeal carcinoma; radiotherapy