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P. Nguyen



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    MO26 - Anatomical Pathology II (ID 129)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Pathology
    • Presentations: 1
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      MO26.06 - Cell block samples from endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) provide sufficient material for ancillary testing in lung cancer. (ID 3262)

      11:00 - 11:05  |  Author(s): P. Nguyen

      • Abstract
      • Presentation
      • Slides

      Background
      Rapid on site examination (ROSE) is encouraged at EBUS-TBNA to improve the yield of this procedure. However, many centres do not have the resources to meet this demand. Due to new therapeutic options in lung cancer, it is not sufficient to merely distinguish between non-small cell lung carcinoma (NSCLC) and small cell lung carcinoma (SCLC). Immunohistochemistry (IHC) distinction where possible is now standard practice, as well additional molecular testing where clinically indicated. We investigated the diagnostic yield of smears vs. cell block and the provision of cellular material for ancillary testing.

      Methods
      A retrospective audit of all EBUS-TBNA procedures performed until the end of July 2012 was undertaken. Diagnostic yield on smears versus cell block was recorded. Cell blocks were reviewed by an experienced pathologist to determine diagnostic accuracy and whether IHC and molecular testing were possible.

      Results
      208 procedures were recorded with 101(48.5%) malignant cases, 81(38.9%) benign cases and 26(12.5%) with insufficient sampling. The average number of passes was 4.5. For malignancies, smear diagnosis was possible in 95% of cases and cell block diagnosis in 93.5% (87/93) of cases. There was sufficient material for IHC in 97.7% (85/87) of malignant cases where required. In 79.3% (69/87) of NSCLCs molecular testing was theoretically possible based on the tumour load of samples obtained.

      Conclusion
      Cell blocks are not inferior to smears for diagnostic accuracy and provide sufficient samples for ancillary testing. However, ROSE assists the physician on how best to manage samples for ancillary testing.

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    O28 - Endoscopy (ID 124)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Pulmonology + Endoscopy/Pulmonary
    • Presentations: 1
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      O28.02 - Grey Scale Texture Analysis of Endobronchial Ultrasound Mini Probe Guide Sheath Images for Prediction of Benign or Malignant Aetiology. (ID 1059)

      10:40 - 10:50  |  Author(s): P. Nguyen

      • Abstract
      • Presentation
      • Slides

      Background
      Expert analysis of endobronchial ultrasound (EBUS) images obtained with the mini probe (MP) has established certain subjective criteria for predicting benign or malignant disease. Minimal data is available for objective analysis of these images. The aim of this study was to determine if greyscale texture analysis of EBUS-MP images could differentiate between benign and malignant peripheral lung lesions.

      Methods
      Digital EBUS-MP images with contrast set at 4 and gain set at 10 were included in this study. A region of interest (ROI) was mapped for each image and analysed in a prediction set. The ROIs were analysed for the following greyscale texture features in MATLAB (v7.8.0.347 (R2009a)); mean pixel value, difference between maximum and minimum pixel value, standard deviation of the mean pixel value, entropy, correlation, energy and homogeneity. Significant greyscale texture features were used to assess a validation set. Figure 1

      Results
      Eighty-five peripheral lung lesions were in the prediction set (47 malignant and 38 benign). Benign lesions had larger differences between maximum and minimum pixel values, larger standard deviations of the mean pixel values and a higher entropy than malignant lesions (p<0.0001 for all values). Eighty two peripheral lesions were in the validation set; 63/82 (76.8%) were correctly classified. Of these 45/49(91.8%) malignant lesions and 18/33 (54.5%) benign lesions were correctly classified. The negative predictive value for malignancy was 82% and the positive predictive value was 75%. Figure 1

      Conclusion
      Greyscale texture analysis of EBUS-MP images could assist in differentiating between benign and malignant peripheral lung lesions but tissue diagnosis is still important.

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    P2.24 - Poster Session 2 - Supportive Care (ID 157)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Supportive Care
    • Presentations: 1
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      P2.24-026 - Lung cancer pathway at the Royal Adelaide Hospital: Impact of treatment intent and patient location. (ID 1605)

      09:30 - 09:30  |  Author(s): P. Nguyen

      • Abstract

      Background
      A previous 2010 audit at the Royal Adelaide Hospital (RAH) found delays in treatment initiation when compared to targets set in the United Kingdom (UK) National Cancer Plan. The aim of this study was to review our performance in 2011 and to explore the impact of curative or palliative treatment intent and rural or urban based location, in order to guide future improvement.

      Methods
      Using a pathology database, we retrospectively reviewed 128 case notes of patients referred to the RAH in 2011 with new histologically confirmed lung cancer. We identified treatment intent, patient location and key dates in diagnosis and treatment by radiation oncology, medical oncology, cardiothoracic surgery or palliative care before calculating median intervals between these points.

      Results
      Figure 1 52% of patients were urban and 48% rural. 45% of patients were treated with curative intent and 55% with palliative intent. Pertinent median intervals include: referral to appointment (appt): 4 days (inpt: 0 days, outpt: 7 days); appt to diagnosis (a) rural outpt :16 days, urban outpt: 10 days (p=0.58); (b) surgical: 21 days, curative outpt CH-R: 7 days (P<0.001); (c) surgical rural 30.5 days, surgical urban 13 days (p<0.001); referral to treatment: 41 days (UK 2006: 41 days, RAH 2010: 48 days, (a) outpt: 54 days, inpt: 21 days (p<0.0001), (b) surgical: 62 days, outpt curative CH-R: 34 days (p=0.81), curative outpt CH-R: 34 days, palliative outpt CH-R: 46.5 days (p=0.79)). Inpts met both UK targets. There are a number of factors contributing to the delays in surgical cases including a higher proportion of cases needing multiple biopsy attempts and requiring CT-FNA, which takes twice as long to obtain as a bronchoscopy. Rural location did not impact on overall time to treatment but delays seen in appointment to diagnosis, in particular the surgical cases.

      Conclusion
      For 2011, the RAH achieved the first UK targets for first appointment to a specialist but did not meet the target set for referral to commencing treatment. Delays were seen in some rural subgroups, necessitating the need for a streamlined rural pathway to assist in managing investigations and appointments. In turn, this will also reduce the number of rural elective admissions. Initiatives to improve time to treatment with curative intent include pre-booking investigations, utilising EBUS for staging and improving access to CT-FNA. A follow up audit including analysis of mortality is being conducted.

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

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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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): P. Nguyen

      • 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.