title: Clinicopathologic predictors of sentinel lymph node metastasis in thin melanoma.
abstract: OBJECTIVE
  Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma.
  
  
  METHODS
  Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome.
  
  
  RESULTS
  SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001).
  
  
  CONCLUSIONS
  Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.
authors.affiliation: Dale Han, Jonathan S. Zager, Sanjana Iyengar, Mia Djulbegovic, Jaimie L. Weber, Suroosh S. Marzban, Vernon K. Sondak, and Jane L. Messina, Moffitt Cancer Center, Tampa; Eli Avisar, University of Miami, Miami, FL; Yu Shyr, Heidi Chen, and Lynne D. Berry, Vanderbilt University School of Medicine, Nashville, TN; John T. Vetto, Oregon Health and Science University, Portland, OR; Richard L. White, Carolinas Medical Center, Charlotte, NC; Barbara Pockaj, Mayo Clinic, Scottsdale; Robert Krouse, Southern Arizona Veterans Administration Health Care System, Tucson, AZ; Nicola Mozzillo, Istituto Nazionale dei Tumori-Fondazione Pascale, Naples, Italy; Kim James Charney, St Joseph Hospital, Orange; and Mohammed Kashani-Sabet and Stanley P. Leong, California Pacific Medical Center and Research Institute, San Francisco, CA.
authors.forename: Dale
authors.initials: D
authors.lastname: Han
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Zager
authors.forename: Yu
authors.initials: Y
authors.lastname: Shyr
authors.forename: Heidi
authors.initials: H
authors.lastname: Chen
authors.forename: Lynne D
authors.initials: LD
authors.lastname: Berry
authors.forename: Sanjana
authors.initials: S
authors.lastname: Iyengar
authors.forename: Mia
authors.initials: M
authors.lastname: Djulbegovic
authors.forename: Jaimie L
authors.initials: JL
authors.lastname: Weber
authors.forename: Suroosh S
authors.initials: SS
authors.lastname: Marzban
authors.forename: Vernon K
authors.initials: VK
authors.lastname: Sondak
authors.forename: Jane L
authors.initials: JL
authors.lastname: Messina
authors.forename: John T
authors.initials: JT
authors.lastname: Vetto
authors.forename: Richard L
authors.initials: RL
authors.lastname: White
authors.forename: Barbara
authors.initials: B
authors.lastname: Pockaj
authors.forename: Nicola
authors.initials: N
authors.lastname: Mozzillo
authors.forename: Kim James
authors.initials: KJ
authors.lastname: Charney
authors.forename: Eli
authors.initials: E
authors.lastname: Avisar
authors.forename: Robert
authors.initials: R
authors.lastname: Krouse
authors.forename: Mohammed
authors.initials: M
authors.lastname: Kashani-Sabet
authors.forename: Stanley P
authors.initials: SP
authors.lastname: Leong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data*; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*; D016019:Survival Analysis; D047368:Tumor Burden; D055815:Young Adult