title: Clinical significance of microscopic melanoma metastases in the nonhottest sentinel lymph nodes.
abstract: OBJECTIVE
  A practice gap exists in the surgical removal of sentinel lymph nodes, from removal of only the most radioactive (hottest) lymph node to removal of all lymph nodes with radioactivity greater than 10% of the hottest lymph node.
  
  
  OBJECTIVE
  To determine the clinical significance of melanoma in sentinel lymph nodes that are not the hottest sentinel node and to determine the risk for disease progression based on sentinel lymph node status and primary tumor characteristics.
  
  
  METHODS
  Consecutive patients with cutaneous melanoma with sentinel lymph nodes resected from January 5, 2004, to June 30, 2008, with a mean follow-up of 59 months, at Massachusetts General Hospital were included in this retrospective review. The last year of follow-up was 2012. The operative protocol led to resection of all sentinel lymph nodes with radioactivity greater than 10% of the hottest lymph node. The number of lymph nodes removed, technetium-99m counts for each sentinel lymph node, presence or absence of sentinel lymph node metastases, primary tumor characteristics, disease progression, and melanoma-specific survival were recorded.
  
  
  METHODS
  Microscopic melanoma metastases in the hottest and nonhottest sentinel lymph nodes and factors that correlate with disease progression and mortality.
  
  
  RESULTS
  A total of 1575 sentinel lymph nodes were analyzed in 475 patients. Ninety-one patients (19%) had positive sentinel lymph nodes. Of these, 72 (79%) had metastases in the hottest sentinel lymph node. Of 19 cases with tumor present, but not in the hottest sentinel lymph node, counts ranged from 26% to 97% of the hottest node. Progression occurred in 43% of patients with sentinel node metastasis, regardless of whether the hottest lymph node was positive. In patients with negative sentinel lymph nodes, 11% developed metastases beyond the sentinel lymph node basin and 3.4% recurred in the basin. Mitogenicity of the primary tumor was associated with mortality (odds ratio, 2.435; 95% CI, 1.351-4.391; P < .001). Removing only the hottest sentinel lymph node would have led to false-negative results in 19 of 475 (4%) of all patients and 19 of 91 patients (21%) with positive sentinel lymph nodes. The 8-year survival in patients with at least 1 positive sentinel lymph node was less than 55%. The presence of more than 1 mitosis per square millimeter in the primary cutaneous melanoma was associated with decreased survival.
  
  
  CONCLUSIONS
  Microscopic melanoma metastases was associated with disease progression and mortality, whether present in the hottest sentinel lymph node or not. These observations emphasize the importance of removing the less hot nodes, addressing a practice gap in the surgical approach to patients with melanoma.
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Su
authors.initials: S
authors.lastname: Luo
authors.affiliation: Pathology Service and Dermatopathology Unit, Massachusetts General Hospital, Harvard Medical School, Boston3Dermatology Department, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Alice Z C
authors.initials: AZ
authors.lastname: Lobo
authors.affiliation: Department of Surgical Oncology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Tanabe
authors.affiliation: Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Alona
authors.initials: A
authors.lastname: Muzikansky
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Tyler
authors.initials: T
authors.lastname: Durazzo
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Arthur
authors.initials: A
authors.lastname: Sober
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Hensin
authors.initials: H
authors.lastname: Tsao
authors.affiliation: Division of Transplant Surgery, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: A Benedict
authors.initials: AB
authors.lastname: Cosimi
authors.affiliation: Center for Melanoma, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Donald P
authors.initials: DP
authors.lastname: Lawrence
authors.affiliation: Pathology Service and Dermatopathology Unit, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Lyn M
authors.initials: LM
authors.lastname: Duncan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008545:Melanoma / Q000175:diagnosis / Q000453:epidemiology / Q000556:secondary*; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms; D055815:Young Adult; D000096142:Cutaneous Malignant Melanoma