title: Radiotherapy in parotid acinic cell carcinoma: does it have an impact on survival?
abstract: OBJECTIVE
  Acinic (or acinar) cell carcinoma (ACC) represents approximately 10% of salivary gland malignant tumors and most commonly occurs in the parotid gland. It carries a propensity for locoregional and distant metastasis. Although it is selectively used as an adjuvant in this tumor, radiotherapy (RT) has not been sufficiently examined in large population studies for survival impact.
  
  
  METHODS
  Retrospective database review.
  
  
  METHODS
  Tertiary care center.
  
  
  METHODS
  A total of 1241 cases of parotid ACC in the Surveillance, Epidemiology, and End Results (SEER) Program database from 1988 to 2007 were identified and analyzed.
  
  
  METHODS
  Comparison groups were surgery and surgery plus RT. Kaplan-Meier survival curves were generated for oncologic stage and histologic grade.
  
  
  METHODS
  Overall survival.
  
  
  RESULTS
  A total of 969 patients had sufficient staging data for inclusion. When comparing surgery with surgery with adjuvant RT, there was no statistical difference in overall survival when stratifying for stage I (P = .57), stage II (P = .37), stage III (P = .25), and stage IV (P = .24) tumors. Similarly, adjuvant RT did not demonstrate a survival advantage when stratified by histologic grade of tumor. The highest-grade and highest-stage tumors were fewer in number, however.
  
  
  CONCLUSIONS
  To our knowledge, this study represents the largest cohort of patients treated for ACC of the parotid. Adjuvant RT does not seem to provide a significant survival advantage for early-stage or lower-grade parotid ACC. Radiotherapy for highest-stage and highest-grade tumors requires further study.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Andreoli
authors.forename: Steven M
authors.initials: SM
authors.lastname: Andreoli
authors.forename: Mark G
authors.initials: MG
authors.lastname: Shrime
authors.forename: Anand K
authors.initials: AK
authors.lastname: Devaiah
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018267:Carcinoma, Acinar Cell / Q000453:epidemiology / Q000532:radiotherapy* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010307:Parotid Neoplasms / Q000453:epidemiology / Q000532:radiotherapy* / Q000601:surgery; D012189:Retrospective Studies; D018426:SEER Program; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology