title: Nasopharyngeal squamous cell carcinoma: a comparative analysis of keratinizing and nonkeratinizing subtypes.
abstract: BACKGROUND
  Nasopharyngeal squamous cell carcinoma (NPSCC) is uncommon in non-endemic regions. Two major histologic subtypes are recognized: keratinizing (K-NPSCC) and nonkeratinizing (NK-NPSCC). We hypothesize that significant differences exist between the 2 in terms of demographic, clinicopathologic, survival, and prognostic features. We aim to show that differentiating between the 2 subtypes is perhaps the most important first step at the time of diagnosis.
  
  
  METHODS
  Using a retrospective cohort design, the U.S. National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry was used to extract data on the 2 major subtypes of NPSCC. Frequency, incidence, and relative survival (RS) were analyzed comparatively. Regression analysis was conducted and hazard ratios (HRs) calculated.
  
  
  RESULTS
  A total of 1624 cases were identified: 1234 (76.0%) cases of NK-NPSCC and 390 (24.0%) cases of K-NPSCC. Five-year RS was 60.6% for NK-NPSCC and 40.5% for K-NPSCC. Regression analysis revealed K-NPSCC to be a poor prognostic factor (HR 2.1; 95% confidence interval, 1.8-2.6; p < 0.0001). Other factors associated with a poor prognosis included female gender in K-NPSCC, age greater than 44 years in both groups, and advanced-stage disease at diagnosis. Favorable prognostic factors included Asian/Pacific Islander race, and treatment with radiation therapy. Higher histologic grade did not portend a worse prognosis for either group.
  
  
  CONCLUSIONS
  NPSCC remains an uncommon malignancy in the United States. K-NPSCC and NK-NPSCC represent 2 different histologic entities with important clinical differences. K-NPSCC carries a worse overall prognosis when compared to NK-NPSCC.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Rutgers New Jersey Medical School, Newark, NJ.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vazquez
authors.forename: Mohemmed N
authors.initials: MN
authors.lastname: Khan
authors.forename: Satish
authors.initials: S
authors.lastname: Govindaraj
authors.forename: Soly
authors.initials: S
authors.lastname: Baredes
authors.forename: Jean Anderson
authors.initials: JA
authors.lastname: Eloy
mesh_terms: D000367:Age Factors; D044466:Asian People; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000473:pathology* / Q000532:radiotherapy; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000532:radiotherapy; D044468:Native Hawaiian or Pacific Islander; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012306:Risk; D012737:Sex Factors; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
chemical_list: D007633:Keratins
keywords: cancers of nasopharynx; keratinizing nasopharyngeal carcinoma; nasopharyngeal cancer; nasopharyngeal neoplasms; nasopharynx cancer; nasopharynx neoplasms; nonkeratinizing nasopharyngeal carcinoma