title: Hot or not? The 10% rule in sentinel lymph node biopsy for malignant melanoma revisited.
abstract: BACKGROUND
  The surgeon needs a practical rule to follow when deciding whether to excise a lymph node during sentinel node biopsy (SLNB). The "10% rule" dictates that all nodes with a radiation count of greater than 10% of the hottest node and all blue nodes should be removed, and this study observes the effects of following this rule in SLNB in melanoma.
  
  
  METHODS
  We reviewed the records of 665 patients with primary melanoma who underwent sentinel lymph node over a 5-year period (2007-2011).
  
  
  RESULTS
  2064 nodes were identified in 898 nodal basins in 665 patients. 141 (21%) patients had at least one positive sentinel node. 105 positive nodal basins were identified in which more than one sentinel node was removed. In 18 of these, a less radioactive node was positive for tumour when the most radioactive node was negative. Of 175 positive nodes 157 (90%) contained blue dye staining. For cases in which the positive sentinel node was not the hottest node, the positive node had apparent blue dye staining in all 18 cases (100%), and was the second hottest node in the basin.
  
  
  CONCLUSIONS
  In this series removing just the hottest node and all blue nodes would not have missed a single positive basin and would have resulted in a 38% reduction in the number of nodes removed compared to those taken following the 10% rule, without changing the staging in any patient.
authors.affiliation: St. George's Melanoma Unit, Dept. of Plastic Surgery, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK. Electronic address: Adrian.murphy@mac.com.
authors.forename: A D
authors.initials: AD
authors.lastname: Murphy
authors.affiliation: Dept. of Medical Physics, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK.
authors.forename: A
authors.initials: A
authors.lastname: Britten
authors.affiliation: St. George's Melanoma Unit, Dept. of Plastic Surgery, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK.
authors.forename: B
authors.initials: B
authors.lastname: Powell
mesh_terms: D004396:Coloring Agents; D003657:Decision Making; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008207:Lymphatic Metastasis; D061305:Lymphoscintigraphy; D008297:Male; D008545:Melanoma / Q000556:secondary*; D008875:Middle Aged; D009367:Neoplasm Staging; D011851:Radioactivity; D012189:Retrospective Studies; D012394:Rosaniline Dyes; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D004396:Coloring Agents; D012394:Rosaniline Dyes; C008769:sulfan blue
keywords: Melanoma; Sentinel node; Staging