title: Prognostic value of tumor thickness in patients with Merkel cell carcinoma.
abstract: OBJECTIVE
  Merkel cell carcinoma is an aggressive skin malignancy that often presents with tumor metastases. We hypothesized that tumor thickness might correlate with both regional and metastatic tumor spread and could, therefore, be used as an independent prognostic variable. The purpose of this study was to see if depth of tumor invasion would predict prognosis independent of tumor stage.
  
  
  METHODS
  Data pertaining to clinical presentation, pathology, treatment, and survival were collected for patients diagnosed with Merkel cell carcinoma from 1972 to 2005. Patients were staged according to AJCC guidelines. Pathologic specimens were evaluated for tumor thickness. The relationship between tumor thickness and disease-free survival or overall survival was analyzed using Kaplan-Meier survival analyses.
  
  
  RESULTS
  Sixty patients were identified. Five-year disease-free survivals for Stages 1, 2, and 3 patients were 20%, 33%, and 0%, respectively. Five-year overall survivals for Stages 1, 2, and 3 patients were 33.3%, 60%, and 16.7%, respectively. There was no correlation between tumor thickness and either disease-free survival or overall survival.
  
  
  CONCLUSIONS
  This study suggests that tumor thickness is not an independent risk factor for survival. Mean tumor thickness did increase with the AJCC stages, but this most likely represents more advanced stage of disease.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, Medical College of Virginia Hospitals/Virginia Commonwealth University, Richmond, Virginia 23298-0645, USA.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Goldberg
authors.forename: James P
authors.initials: JP
authors.lastname: Neifeld
authors.forename: William J
authors.initials: WJ
authors.lastname: Frable
mesh_terms: D000368:Aged; D015266:Carcinoma, Merkel Cell / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology*; D015996:Survival Rate