title: PET-CT in presurgical lymph node staging in non-small cell lung cancer: the importance of false-negative and false-positive findings.
abstract: OBJECTIVE
  To assess the importance of false-negative and false-positive findings in computed tomography (CT) and18F-FDG positron emission tomography (PET) in mediastinal lymph node staging in patients undergoing surgery for non-small cell lung cancer (NSCLC).
  
  
  METHODS
  This retrospective study included 113 consecutive patients and 120 resected NSCLCs; 22 patients received neoadjuvant treatment. We compared the findings on preoperative18F-FDG PET-CT studies with the postoperative pathology findings. Lymph node size and primary tumor size were measured with CT, and lymph nodes and primary tumors were evaluated qualitatively and semiquantitatively (using standardized uptake values (SUVmax)) with PET.
  
  
  RESULTS
  Metastatic lymph nodes were found in 26 (21.7%) of the 120 tumors and in 41 (7.7%) of the 528 lymph node stations analyzed.18F-FDG PET-CT yielded 53.8% sensitivity, 76.6% specificity, 38.9% positive predictive value, 85.7% negative predictive value, and 71.7% diagnostic accuracy. The false-negative rate was 14.2%. Multivariable analysis found that the factors associated with false-negative findings were a moderate degree of differentiation in the primary tumor (p = 0.005) and an SUVmax of the primary tumor >4 (p = 0.027). The false-positive rate was 61.1%, and the multivariable analysis found that lymph node size >1cm was associated with false-positive findings (p < 0.001).
  
  
  CONCLUSIONS
  In mediastinal lymph node staging in patients with NSCLC,18F-FDG PET-CT improves the specificity and negative predictive value and helps clinicians to select the patients that will benefit from surgery. Given the high rate of false positives, histological confirmation of positive cases is recommendable.
authors.affiliation: Servicio de Radiodiagnóstico, Hospital Clínico San Carlos, Madrid, España. Electronic address: abustos.hcsc@salud.madrid.org.
authors.forename: A
authors.initials: A
authors.lastname: Bustos García de Castro
authors.affiliation: Servicio de Radiodiagnóstico, Hospital Clínico San Carlos, Madrid, España.
authors.forename: J
authors.initials: J
authors.lastname: Ferreirós Domínguez
authors.affiliation: Departamento de Diagnóstico por Imagen y Medicina Nuclear, Hospital de La Rioja, Logroño, España.
authors.forename: R
authors.initials: R
authors.lastname: Delgado Bolton
authors.affiliation: Instituto de Investigación Sanitaria San Carlos, Universidad Complutense de Madrid, Madrid, España.
authors.forename: C
authors.initials: C
authors.lastname: Fernández Pérez
authors.affiliation: Servicio de Radiodiagnóstico, Hospital Clínico San Carlos, Madrid, España.
authors.forename: B
authors.initials: B
authors.lastname: Cabeza Martínez
authors.affiliation: Servicio de Radiodiagnóstico, Hospital Clínico San Carlos, Madrid, España.
authors.forename: M
authors.initials: M
authors.lastname: García García-Esquinas
authors.affiliation: Servicio de Medicina Nuclear, Hospital Clínico San Carlos, Madrid, España.
authors.forename: J L
authors.initials: JL
authors.lastname: Carreras Delgado
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008297:Male; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D011300:Preoperative Care; D012189:Retrospective Studies
keywords: Carcinoma de pulmón de células no pequeñas; Estadificación tumoral; Helical computed tomography; Imagen multimodalidad; Multimodality imaging; Non-small cell lung cancer; Positron emission tomography; Tomografía computarizada helicoidal; Tomografía por emisión de positrones; Tumor staging