title: Raman spectroscopy: a novel experimental approach to evaluating renal tumours.
abstract: BACKGROUND
  New optical techniques of spectroscopy have shown promising results in the evaluation of solid tumours.
  
  
  OBJECTIVE
  To evaluate the potential of Raman spectroscopy (RS) to assess renal tumours at surgery.
  
  
  METHODS
  Over a 5-mo period, Raman optical spectra were prospectively acquired on surgical renal specimens removed due to suspicion of cancer.
  
  
  METHODS
  Raman measures were normalised to ensure comparison between spectra. A lower resolution signal was computed using a wavelet decomposition procedure to diminish the size of the signal and exploit the complete spectrum. A support vector machine (SVM) with a linear kernel and a sequential minimal optimisation solver was applied. A leave-one-out cross-validation technique was used to train and test the SVM.
  
  
  CONCLUSIONS
  There were 36 patients with 34 malignant tumours (27 clear-cell, 6 papillary, and 1 chromophobe) and 2 benign (1 oncocytoma and 1 metanephric cyst) tumours. A total of 241 analysable Raman spectra were obtained. The SVM was able to classify tumoural and normal tissue with an accuracy of 84% (sensitivity 82%, specificity 87%). High-grade and low-grade tumours were differentiated with a precision of 82% (sensitivity 84%, specificity 80%). Histologic subtype could be categorised with an accuracy of 93% (sensitivity 96%, specificity 87%). SVM could not be applied to classify benign and malignant tumours because of the restricted number of benign spectra.
  
  
  CONCLUSIONS
  RS can accurately differentiate normal and tumoural renal tissue, low-grade and high-grade renal tumours, and histologic subtype of renal cell carcinoma. Larger prospective studies are needed to confirm these preliminary data.
authors.affiliation: Inserm, U 642, Rennes, F-35000, France. karim.bensalah@chu-rennes.fr
authors.forename: Karim
authors.initials: K
authors.lastname: Bensalah
authors.forename: Julien
authors.initials: J
authors.lastname: Fleureau
authors.forename: Denis
authors.initials: D
authors.lastname: Rolland
authors.forename: Olivier
authors.initials: O
authors.lastname: Lavastre
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rioux-Leclercq
authors.forename: François
authors.initials: F
authors.lastname: Guillé
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Patard
authors.forename: Lotfi
authors.initials: L
authors.lastname: Senhadji
authors.forename: Renaud
authors.initials: R
authors.lastname: de Crevoisier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008875:Middle Aged; D011446:Prospective Studies; D013059:Spectrum Analysis, Raman