title: Histologic grade as prognostic indicator for mucoepidermoid carcinoma: a population-level analysis of 2400 patients.
abstract: BACKGROUND
  Mucoepidermoid carcinoma (MEC) is an uncommon malignancy. To the best of our knowledge, this is the largest study investigating disease-specific survival (DSS) of parotid MEC and the first population-level study of the distribution of nodal metastases.
  
  
  METHODS
  Patients with MEC of the parotid gland were identified in the Surveillance, Epidemiology, and End Results (SEER) database (1988-2009).
  
  
  RESULTS
  We identified 2400 patients with MEC: 522 low grade, 1137 intermediate grade, and 741 high grade. Five-year DSS rates for low-grade, intermediate-grade, and high-grade MEC were 98.8%, 97.4%, and 67.0%, respectively (p < .001). Negative prognostic factors included high grade, increasing patient age, and tumor size, extraparenchymal extension, nodal metastases, and distant metastases. High-grade MEC was more likely to have lymph node metastases in levels I to III (34.0%) than low-grade (3.3%) and intermediate-grade MEC (8.1%; p < .001).
  
  
  CONCLUSIONS
  Grade influences the prognosis and distribution of nodal metastases. Results indicate that management guidelines should vary based on grade.
authors.affiliation: Department of Surgery, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Chen
authors.forename: Sanziana A
authors.initials: SA
authors.lastname: Roman
authors.forename: Julie A
authors.initials: JA
authors.lastname: Sosa
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Judson
mesh_terms: D000368:Aged; D018277:Carcinoma, Mucoepidermoid / Q000453:epidemiology / Q000473:pathology* / Q000532:radiotherapy; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D010307:Parotid Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000532:radiotherapy; D011379:Prognosis; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
keywords: lymph node metastases; mucoepidermoid carcinoma; parotid gland; salivary gland carcinoma; survival