title: Adenoid cystic carcinoma of the external ear: a population based study.
abstract: OBJECTIVE
  To determine the incidence of adenoid cystic carcinoma of the external ear in the United States, and to evaluate the clinical characteristics and survival outcomes associated with the disease.
  
  
  METHODS
  Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) 18 Database of the National Cancer Institute. The study cohort included patients diagnosed with adenoid cystic carcinoma of the external ear from 1973 to 2012.
  
  
  RESULTS
  The incidence of adenoid cystic carcinoma of the external ear was 0.004 per 100,000. The SEER database identified 66 patients meeting the inclusion criteria. Nodal metastasis was noted in 13.1% of patients, while 7.9% had distant metastasis. Distant metastasis was associated with worse overall survival (HR 10.18). However, nodal metastasis had no impact on overall survival (HR 0.15, p = 0.09). Surgery alone was associated with improved overall survival (HR 0.26), compared with combination surgery and radiotherapy, while radiotherapy alone was associated with worse overall survival (HR 20.12). Increasing age (HR 1.12) and black race (HR 6.83) were associated with worse overall survival, while female sex (HR 0.26) was associated with improved overall survival.
  
  
  CONCLUSIONS
  ACC of the external ear is rare. Distant metastasis is a poor prognostic factor. However, nodal metastasis does not appear to impact survival. Advanced age, black race, and male sex are also poor prognostic factors. Surgical resection alone is associated with better survival than combination surgical resection and radiation, or radiotherapy alone.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Ross W
authors.initials: RW
authors.lastname: Green
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA. Electronic address: megwaluu@yahoo.com.
authors.forename: Uchechukwu C
authors.initials: UC
authors.lastname: Megwalu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003528:Carcinoma, Adenoid Cystic / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D004428:Ear Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D004431:Ear, External; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018426:SEER Program; D015996:Survival Rate; D014481:United States; D055815:Young Adult