title: Melanoma metastases in regional lymph nodes are accurately detected by proton magnetic resonance spectroscopy of fine-needle aspirate biopsy samples.
abstract: BACKGROUND
  Nonsurgical assessment of sentinel nodes (SNs) would offer advantages over surgical SN excision by reducing morbidity and costs. Proton magnetic resonance spectroscopy (MRS) of fine-needle aspirate biopsy (FNAB) specimens identifies melanoma lymph node metastases. This study was undertaken to determine the accuracy of the MRS method and thereby establish a basis for the future development of a nonsurgical technique for assessing SNs.
  
  
  METHODS
  FNAB samples were obtained from 118 biopsy specimens from 77 patients during SN biopsy and regional lymphadenectomy. The specimens were histologically evaluated and correlated with MRS data. Histopathologic analysis established that 56 specimens contained metastatic melanoma and that 62 specimens were benign. A linear discriminant analysis-based classifier was developed for benign tissues and metastases.
  
  
  RESULTS
  The presence of metastatic melanoma in lymph nodes was predicted with a sensitivity of 92.9%, a specificity of 90.3%, and an accuracy of 91.5% in a primary data set. In a second data set that used FNAB samples separate from the original tissue samples, melanoma metastases were predicted with a sensitivity of 87.5%, a specificity of 90.3%, and an accuracy of 89.1%, thus supporting the reproducibility of the method.
  
  
  CONCLUSIONS
  Proton MRS of FNAB samples may provide a robust and accurate diagnosis of metastatic disease in the regional lymph nodes of melanoma patients. These data indicate the potential for SN staging of melanoma without surgical biopsy and histopathological evaluation.
authors.affiliation: Sydney Melanoma Unit and Melanoma and Skin Cancer Research Institute, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050, Australia.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Stretch
authors.forename: Ray
authors.initials: R
authors.lastname: Somorjai
authors.forename: Roger
authors.initials: R
authors.lastname: Bourne
authors.forename: Edward
authors.initials: E
authors.lastname: Hsiao
authors.forename: Richard A
authors.initials: RA
authors.lastname: Scolyer
authors.forename: Brion
authors.initials: B
authors.lastname: Dolenko
authors.forename: John F
authors.initials: JF
authors.lastname: Thompson
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Mountford
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Lean
mesh_terms: D044963:Biopsy, Fine-Needle; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D009682:Magnetic Resonance Spectroscopy; D008545:Melanoma / Q000175:diagnosis* / Q000556:secondary*; D011522:Protons; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy
chemical_list: D011522:Protons