title: Sentinel node biopsy improves prognostic stratification in patients with thin (pT1) melanomas and an additional risk factor.
abstract: BACKGROUND
  Sentinel lymph node (SLN) biopsy (SLNB) for pT1 melanomas is not generally recognized as a clinical standard. We studied the value of SLNB for pT1 melanoma patients having at least one additional risk factor.
  
  
  METHODS
  Among 931 patients with SLNB, 210 had pT1 melanomas. All of the latter showed at least one of the following risk factors: ulceration (4 %) Clark level IV (44 %), nodular growth pattern (11 %), mitoses (59 %), regression (38 %) or age ≤ 40 years (27 %).
  
  
  RESULTS
  In this selected pT1 population, we observed a surprisingly high SLN positivity rate of 18 %. The melanoma-specific overall survival significantly depended on SLN status. Compared with Clark IV, a lower invasion level (Clark II/III) was associated with a higher proportion of positive SLNs (25 vs. 10 %; p < 0.01). There was a trend towards a higher SLN positivity rate in younger patients (p = 0.06). Breslow, ulceration, mitoses, nodular growth pattern, and sex did not reach significance. Regression was significantly more frequently found in very thin melanomas (≤ 0.75 mm) and tended to be significant in this subgroup (p = 0.075).
  
  
  CONCLUSIONS
  SLNB improves prognostic stratification in patients with thin melanomas having an additional risk factor. Clark level IV most likely does not belong to these risk factors. The impact of regression deserves further consideration. Our data suggest that SLNB should be offered to patients with thin melanomas, if ulceration, nodular growth pattern, mitoses, or regression are present, or if the patient is younger than 40 years of age.
authors.affiliation: Department of Dermatology, Venereology and Allergology, Klinikum Hildesheim GmbH, Hildesheim, Germany, christina.mitteldorf@klinikum-hildesheim.de.
authors.forename: Christina
authors.initials: C
authors.lastname: Mitteldorf
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Bertsch
authors.forename: Klaus
authors.initials: K
authors.lastname: Jung
authors.forename: Kai-Martin
authors.initials: KM
authors.lastname: Thoms
authors.forename: Michael Peter
authors.initials: MP
authors.lastname: Schön
authors.forename: Michael
authors.initials: M
authors.lastname: Tronnier
authors.forename: Lutz
authors.initials: L
authors.lastname: Kretschmer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012307:Risk Factors; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate; D055815:Young Adult