title: Merkel cell carcinoma: identification of prognostic factors unique to tumors located in the head and neck based on analysis of SEER data.
abstract: OBJECTIVE
  Merkel cell carcinoma (MCC) is an aggressive cutaneous neoplasm that occurs most frequently in the head and neck region. Because of its rarity, prognostic factors are poorly characterized. Head and neck MCC (HN-MCC) may require separate consideration from MCC that occurs in other anatomic regions. Our objective was to determine the relevance of clinicopathologic parameters as prognostic factors in a large series of patients with HN-MCC and to compare these to a series of patients with non-head and neck MCC (NHN-MCC).
  
  
  METHODS
  Retrospective analysis of large population database.
  
  
  METHODS
  Patients with MCC were identified using the Surveillance, Epidemiology, and End Results database and categorized according to tumor location either 1) within or 2) outside of the head and neck region. Clinicopathologic data were compared between groups. Retrospective univariable and multivariable analyses of factors associated with disease-specific survival (DSS) were performed.
  
  
  RESULTS
  We identified 2,104 patients with HN-MCC and 2,272 with NHN-MCC. DSS was similar between groups. Independent prognostic factors in HN-MCC are male sex (P < .001), lip primary site (P = .005), tumor extension beyond the dermis (P = .03), histologically confirmed nodal disease (P < .001), absence of histologic lymph node evaluation (P = .01), and distant metastasis (P = .001). Male sex and tumor extension limited to the subcutis are prognostic factors that are unique to HN-MCC.
  
  
  CONCLUSIONS
  Because independent markers of aggressive disease appear to be unique in HN-MCC, it is important that future studies provide separate consideration for HN-MCC to allow for the most accurate identification of prognostic indicators and assessment of treatment outcomes accordingly.
authors.affiliation: College of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Smith
authors.forename: E Ramsay
authors.initials: ER
authors.lastname: Camp
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Lentsch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000032:analysis; D015266:Carcinoma, Merkel Cell / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D018426:SEER Program; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy; D016019:Survival Analysis; D016896:Treatment Outcome; D014481:United States
chemical_list: D014408:Biomarkers, Tumor