Author of

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  P3.19 - Poster Session 3 - Imaging (ID 181)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Imaging, Staging & Screening
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12795

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    P3.19-004 - Comparison of objective criteria and expert visual interpretation to classify benign and malignant hilar and mediastinal nodes on 18-F FDG PET/CT. (ID 1398)

    09:30 - 09:30  |  Author(s): A. Ravi Kumar
    • Abstract

    Background
    Despite the widespread adoption of FDG-PET/CT in staging of lung cancer, there are no universally accepted criteria for classifying thoracic nodes as malignant. Previous studies have generally shown high negative predictive values, but there are varying reporting criteria and positive predictive values for classifying malignant involvement. Using Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) histology as the gold standard, we evaluated objective 18-F FDG-PET/CT criteria for interpreting mediastinal and hilar nodes and compared this to expert visual interpretation (EVI).

    Methods
    A retrospective review of all patients with proven/suspected primary lung cancer who had both FDG-PET/CT and EBUS-TBNA from 2008-2010 was performed. Scan interpretation was blinded to histology. Separate prediction and validation datasets were used. 104 patients from 2008/2009 formed the prediction set; 48 patients from 2010 formed the validation set. Objective FDG-PET/CT criteria were: - SUVmax lymph node (SUVmaxLN) - Ratio SUVmaxLN/SUVmax primary lung malignancy if evident (R-SUVmax primary) - Ratio SUVmaxLN/SUVaverage liver (R-SUVavg liver) - Ratio SUVmaxLN/SUVmax liver (R-SUVmax liver) - Ratio SUVmaxLN/SUVmax blood pool (R-SUVmaxBP) An experienced Nuclear Medicine Physician visually reviewed all scans and classified each thoracic nodal station as benign, malignant, or equivocal. For statistical analysis, ‘equivocal’ nodes were classified benign.

    Results
    87 malignant lymph nodes from 75 patients and 41 benign nodes from 21 patients were in the prediction set. All objective 18-F FDG-PET/CT criteria analysed were significantly higher in the malignant group compared to the benign group (p<0.0001 all criteria). EVI had 95.3% accuracy, with 83/87(95.4%) malignant nodes and 39/41(95.1%) benign nodes correctly classified. 34 malignant nodes from 34 patients and 19 benign nodes from 14 patients were in the validation set. The new proposed cut-off values of the objective criteria from the prediction set correctly classified 44/53(83.0%) nodes, with 28/34(82.4%) malignant nodes and 16/19(84.2%) benign nodes correctly classified. EVI had 91% accuracy, with 33/34(97.1%) malignant nodes and 15/19 (79.0%) benign nodes correctly classified. Figure 1

    Conclusion
    Objective analysis of 18-F FDG PET/CT can differentiate between malignant and benign nodes with high accuracy, but is not superior to EVI. For objective criteria to perform optimally, there may need to be different criteria devised for different patient populations.