title: Both tumor depth and diameter are predictive of sentinel lymph node status and survival in Merkel cell carcinoma.
abstract: BACKGROUND
  The purposes of this study were 1) to determine the impact of primary tumor-related factors on the prediction of the sentinel lymph node (SLN) status and 2) to identify clinical and pathologic factors associated with survival in Merkel cell carcinoma (MCC).
  
  
  METHODS
  An institutional review board-approved, retrospective review of patients with MCC treated between 1988 and 2011 at a single center was performed. Patients were categorized into 5 groups: 1) negative SLN, 2) positive SLN, 3) clinically node-negative but SLN biopsy not performed, 4) regional nodal disease without a known primary tumor, and 5) primary MCC with synchronous clinically evident regional nodal disease. Factors predictive of the SLN status were analyzed with logistic regressions, and overall survival (OS) and disease-specific survival (DSS) were analyzed with Cox models and competing risk models assuming proportional hazards, respectively.
  
  
  RESULTS
  Three hundred seventy-five patients were analyzed, and 70% were male; the median age was 75 years. The median tumor diameter was 1.5 cm (range, 0.2-12.5 cm), and the median tumor depth was 4.8 mm (range, 0.3-45.0 mm). One hundred ninety-one patients underwent SLN biopsy, and 59 (31%) were SLN-positive. Increasing primary tumor diameter and increasing tumor depth were associated with SLN positivity (P = .007 and P = .017, respectively). Age and sex were not associated with the SLN status. Immunosuppression, increasing tumor diameter, and increasing tumor depth were associated with worse OS (P = .007, P = .003, and P = .025, respectively). DSS differed significantly by group and was best for patients with a negative SLN and worst for those with primary MCC and synchronous clinically evident nodal disease (P = .018).
  
  
  CONCLUSIONS
  For patients with MCC, increasing primary tumor diameter and increasing tumor depth are independently predictive of a positive SLN, worse OS, and worse DSS. Tumor depth should be routinely reported when primary MCC specimens are being evaluated histopathologically.
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Franz O
authors.initials: FO
authors.lastname: Smith
authors.affiliation: Department of Biostatistics, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Binglin
authors.initials: B
authors.lastname: Yue
authors.affiliation: Morsani College of Medicine, University of South Florida, Tampa, Florida.
authors.forename: Suroosh S
authors.initials: SS
authors.lastname: Marzban
authors.affiliation: Department of Dermatology, Brigham and Women's Hospital, Brookline, Massachusetts.
authors.forename: Brooke L
authors.initials: BL
authors.lastname: Walls
authors.affiliation: Morsani College of Medicine, University of South Florida, Tampa, Florida.
authors.forename: Michael
authors.initials: M
authors.lastname: Carr
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of South Florida, Tampa, Florida.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Jackson
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Puleo
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of South Florida, Tampa, Florida.
authors.forename: Tapan
authors.initials: T
authors.lastname: Padhya
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: C Wayne
authors.initials: CW
authors.lastname: Cruse
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Gonzalez
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Amod A
authors.initials: AA
authors.lastname: Sarnaik
authors.affiliation: Department of Biostatistics, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schell
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: DeConti
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.|Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Jane L
authors.initials: JL
authors.lastname: Messina
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Vernon K
authors.initials: VK
authors.lastname: Sondak
authors.affiliation: Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Zager
mesh_terms: D000368:Aged; D015266:Carcinoma, Merkel Cell / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology*
keywords: Merkel cell carcinoma; sentinel lymph node; survival; tumor depth; tumor diameter