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A. Akkoclu



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    O23 - Imaging and Screening (ID 125)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      O23.07 - Comparison of diffusion-weighted magnetic resonance imaging versus<br /> F-18 fluorodeoxyglucose positron emission tomography in the assessment of N2 lymph node metastasis due to non-small cell lung cancer (ID 350)

      16:15 - 17:45  |  Author(s): A. Akkoclu

      • Abstract
      • Presentation
      • Slides

      Background
      To compare the diagnostic efficacies of diffusion-weighted magnetic resonance imaging (DWI) and F-18 fluorodeoxyglucose positron emission tomography (PET) findings for the preoperative prediction of mediastinal nodal metastasis in stage N2 disease of non–small cell lung cancer (NSCLC).

      Methods
      The study included 68 patients (42 men and 26 women; mean age, 62 years) with a supicious stage N2 due to NSCLC. In all patients, DWI (using a sigle-shot echo-planar sequence with diffusion factor of 0-600 s/mm² at 1.5 Tesla) and PET were performed before surgery. In DWI, a patient was regarded to have stage N2 disease when an ipsilateral mediastinal lymph node showed apparent diffusion coefficent (ADC) value of ≤0.98 s/mm², regardless of nodal size. A node was considered as positive for malignancy, if it showed standardized uptake value (SUV) of 3 or higher by PET. Both DWI and PET images were prospectively evaluated for malignancy on a per-node basis by two observers. Histopathologic results served as the reference standard. N2 disease was decided by using the American Joint Committee on Cancer staging system. The results were compared between the two modalities and statistically significant differences in nodal metastasis between DWI and PET were determined with p<.05 obtained by using the McNemar test or with a generalized estimating equation.

      Results
      Nodes were positive for malignancy in 36 (32%) of 114 nodal stations and 22 (32%) of 68 patients. The N2 staging was correctly diagnosed in 56 (82%) and 52 (76%) patients by DWI and PET (p=.09), respectively. For the depiction of malignant nodes, DWI and PET showed sensitivities of 78% (31 of 40 nodal groups) and 78% (28 of 36), specificities of 93% (69 of 74) and 90% (70 of 78), positive predictive values of 86% (31 of 36) and 78% (28 of 36), negative predictive values of 88% (69 of 78) and 90% (70 of 78) and accuracies of 88% (100 of 104) and 86% (91 of 104), respectively (p=.23, p<.05, p<.01, p=.08, and p=.12). There were nine false-positive interpretations by DWI, compared with eight by PET. Eight false-negative assessments were present on PET images, but only five false-negative results were found in DWI. .Figure 1

      Conclusion
      DWI has a higher specificity for N2 staging of NSCLC compared with PET and has the potential to be a reliable alternative imaging method with an advantage of radiation-free imaging for the preoperative staging of mediastinal lymph nodes in patients with NSCLC.

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    P1.12 - Poster Session 1 - NSCLC Early Stage (ID 203)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Medical Oncology
    • Presentations: 1
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      P1.12-004 - Accuracy of PET/CT in the Evaluation of N1 and N2 Lymph Node Stations in Operable NSCLC (ID 1181)

      09:30 - 16:30  |  Author(s): A. Akkoclu

      • Abstract

      Background
      Aim: Mediastinal lymph node metastases are frequent in non small cell carcinomas (NSCLC). We aimed to investigate the diagnostic accuracy of PET-CT for different mediastinal lymph nodes in operable NSCLC patients by comparing PET-CT results with cervical mediastinoscopy and thoracotomy findings.

      Methods
      Methods: Medical records of 124 operable NSCLC patients to whom PET-CT was applied for clinical staging between November 2009 and December 2011 were evaluated retrospectively. PET-CT was negative in 64 of 124 patients. Thirty-four of the patients underwent cervical mediastinoscopy, 4 underwent anterior mediastinotomy, 3 underwent thoracotomy and the remaining 83 were operated without any prior invasive procedure. PET/CT uptake of different stations were explored, sensitivity, specifity, negative (NPV) and positive predictive (PPV) values and accuracy rates were calculated

      Results
      Results: Sensitivity, specifity, PPV, NPV and accuracy rates for N1 and N2 lymph nodes are shown in the table. Accuracy rates were low for 4th, 7th and 10th numbered lymph nodes. However any significant correlation was not observed between pathology and PET-CT for nodal stations 3 and 10.

      % Sensitivity Specifity PPV NPV Accuracy
      N1 8 94 21 82 78
      N2 57 93 49 95 89

      Conclusion
      Conclusion: The lower rates of PET-CT sensitivity and PPV for N1 lymph nodes than N2 lymph nodes reflect the poor success rates of N1 determination with PET-CT. The lower accuracy rates of 4, 7 and 10 station lymph nodes with PET-CT as well as the pathology and PET-CT uncorrelation for 3 and 10 lymph nodes might be explained by the close localization of these stations to N1 lymph nodes and the restriction of the PET-CT in discrimination of N2 lymph nodes from N1 in this area.

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    P2.19 - Poster Session 2 - Imaging (ID 180)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P2.19-001 - The Imaging Characteristics of F-18 FDG PET-CT on Epidermal Growth Factor Receptor Mutations in Non-small cell Lung Cancer (ID 291)

      09:30 - 16:30  |  Author(s): A. Akkoclu

      • Abstract

      Background
      Aim: We aimed to compare F-18 FDG PET-CT imaging characterictics in non-small cell lung cancer (NSCLC) with and without epidermal growth factor (EGFR) reseptor mutation.

      Methods
      Methods: A total of 47 NSCLC patients (38 male, 9 female, mean age : 47±10.45 )were included in this retrospective study. All patients underwent EGFR mutation resting and pretreatment F-18 FDG PET-CT scan. The maksimum standardized uptake (SUVmax) of the primary tumor and metastases was calculated for all lesions in all patients. We compared the SUVmax values for primary tumor and metastatic lesions in patients with and without EGFR receptor mutation.

      Results
      Results: In our study group, there were 17 adeno, 10 squamous, 2 large cell, 1 mixt-type and 17 non-small cell cancer patients. Seven patients had EGFR-mutant and 40 patients had EGFR wild-type tumors. There was a trend for higher SUVmax in primary tumors among patients with EGFR-mutant (mean SUVmax: 14.20±10.40) versus patients with wild-type EGFR (mean SUVmax:11.53±6.46). In patients with wild-type EGFR, the mean SUVmax was 7.05±3.39, 7.83±4.66, 6.10±4.44, 12.83±4.89 for hilar(17 pts), unilateral mediastinal (23 pts), contralateral mediastinal (13pts) and supraclavicular (3 pts) lymph node metastates (LNM), respectively. In 5 patients with EGFR-mutant , SUVmax was 6.48±3.39 for unilateral mediastinal LNM. There was no hilar, contralateral and supraclavicular LNM which can be demonstrated by F-18 FDG PET-CT in EGFR-mutant patients. The mean SUVmax was 7.97±6.67, 8.98±4.31 and 5.85±3.39 for lung (6 pts), bone (9 pts) and adrenal (6 pts) metastases in wild- type EGFR patient group. In EGFR-mutant group , one patient had lung, bone and adrenal metastases in which SUVmax was 4.20, 11.20 and 22.20, respectively.

      Conclusion
      Conclusion: Higher FDG uptake was found in primary tumors among EGFR-mutant patients than wild-type EGFR patients. In this study group, the incidence of hilar, contralateral mediastinal and supraclavicular LNM were higher in wild-type EGFR group than that in EGFR-mutant group. Bone and adrenal metastases in a patient with EGFR-mutant showed markedly increased FDG uptake. Further analyses with large number of patients are needed to describe a predictive role of FDG uptake on EGFR mutations in NSCLC patients.