title: Predictors of Nodal Metastasis in Parotid Malignancies: A National Cancer Data Base Study of 22,653 Patients.
abstract: OBJECTIVE
  (1) To identify predictors of nodal disease in parotid malignancies using various clinical and pathologic variables. (2) To examine the effect of nodal disease on overall survival (OS) in parotid cancers
  
  
  METHODS
  Retrospective database review.
  
  
  METHODS
  National Cancer Data Base (1998-2012).
  
  
  METHODS
  We identified all cases of primary parotid malignancies in the United States between 1998 and 2012 in the National Cancer Data Base. Eight histopathologies, constituting >80% of all cases, were examined for nodal metastasis and survival.
  
  
  RESULTS
  We identified 22,653 cases of primary parotid cancer. Eight major histologies were studied, with mucoepidermoid carcinoma (31%), acinic cell carcinoma (18%), adenocarcinoma (14%), and adenoid cystic carcinoma (9%) being most common. Regional nodal disease incidence was 24.4% overall and varied by histopathology. Salivary ductal carcinoma had the highest incidence of both nodal metastasis and occult lymph node metastasis. Overall, N0 patients lived significantly longer than N+ (5-year OS, 79% vs 40%; P < .001). Low-grade disease had significantly better survival than high-grade (5-year OS, 88% vs 69%; P < .001). Occult nodal disease was found in 10.2% and varied by histopathology.
  
  
  CONCLUSIONS
  Regional lymph node metastasis significantly decreases survival in many parotid malignancies. High-grade cancers had higher incidences of regional disease than did low grade. Adenocarcinoma had the highest mortality when regional disease was present. Incidence of occult disease varied by histology, but incidence was <10% for all low-grade disease. High T stage and grade are significant independent predictors of nodal disease for most histopathologies.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Xiao
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: Kevin Y
authors.initials: KY
authors.lastname: Zhan
authors.affiliation: Cancer Registry, Hollings Cancer Center, Charleston, South Carolina, USA.
authors.forename: Shai J
authors.initials: SJ
authors.lastname: White-Gilbertson
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA headneck@musc.edu.
authors.forename: Terry A
authors.initials: TA
authors.lastname: Day
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010307:Parotid Neoplasms / Q000401:mortality / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate
keywords: nodal disease; occult disease; parotid cancer; parotid malignancy