title: Should all patients with melanoma between 1 and 2 mm Breslow thickness undergo sentinel lymph node biopsy?
abstract: BACKGROUND
  Sentinel lymph node (SLN) biopsy generally is recommended for patients who have melanoma with a Breslow thickness > or = 1 mm. Most patients with melanoma between 1 mm and 2 mm thick have tumor-negative SLNs and an excellent long-term prognosis. The objective of the current study was to evaluate prognostic factors in this subset of patients and determine whether all such patients require SLN biopsy.
  
  
  METHODS
  Patients with melanoma between 1 mm and 2 mm in Breslow thickness were evaluated from a prospective multi-institutional study of SLN biopsy for melanoma. Disease-free survival (DFS) and overall survival (OS) were evaluated by Kaplan-Meier analysis to compare patients with melanoma that measured from 1.0 mm to 1.59 mm (Group A) versus patients with melanoma that measured from > or = 1.6 mm to 2.0 mm thick (Group B). Univariate and multivariate analyses were performed to evaluate factors predictive of tumor-positive SLN status, DFS, and OS.
  
  
  RESULTS
  The current analysis included 1110 patients with a median follow-up of 69 months. SLN status was tumor-positive in 133 of 1110 patients (12%) including 66 of 762 patients (8.7%) in Group A and 67 of 348 patients (19.3%) in Group B (P < .0001). On multivariate analysis, age, Breslow thickness, and lymphovascular invasion were independently predictive of a tumor-positive SLN (P < .05). DFS (P < .0001) and OS (P = .0001) were significantly better for Group A than for Group B. When tumor thickness was treated as either a continuous variable (P < 0.0001) or a categorical variable (P < .0001), it was significantly predictive of DFS and OS. On multivariate analysis, Breslow thickness, age, ulceration, histologic subtype, regression, Clark level, and SLN status were significant factors predicting DFS; and Breslow thickness, age, primary tumor location, sex, ulceration, and SLN status were significant factors predicting OS (P < .05). A subgroup of patients who had tumors <1.6 mm in Breslow thickness, had no lymphovascular invasion, and were aged > or = 59 years had a low risk (5%) of tumor-positive SLN.
  
  
  CONCLUSIONS
  The current findings indicated that there is significant diversity in the biologic behavior of melanoma between 1 mm and 2 mm in Breslow thickness. SLN biopsy is recommended for all such patients to identify those with lymph node metastasis who are at the greatest risk of recurrence and mortality.
authors.affiliation: Department of Surgery, University of Louisville, Louisville, Kentucky, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Mays
authors.forename: Robert C G
authors.initials: RC
authors.lastname: Martin
authors.forename: Alison
authors.initials: A
authors.lastname: Burton
authors.forename: Brooke
authors.initials: B
authors.lastname: Ginter
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Edwards
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Reintgen
authors.forename: Merrick I
authors.initials: MI
authors.lastname: Ross
authors.forename: Marshall M
authors.initials: MM
authors.lastname: Urist
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Stromberg
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McMasters
authors.forename: Charles R
authors.initials: CR
authors.lastname: Scoggins
mesh_terms: D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018570:Risk Assessment; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000473:pathology*