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The mediastinal staging accuracy of 18F-Fluorodeoxyglycose positron emission tomography/computed tomography in non-small cell lung cancer with variable time intervals to surgery.

Booth K, Hanna GG, McGonigle N, McManus KG, McGuigan J, O'Sullivan J, Lynch T, McAleese J - Ulster Med J (2013)

Bottom Line: Those scanned <9 weeks before pathological sampling were significantly more sensitive (64% >9 weeks, 0% ≥ 9 weeks, p=0.013) and more accurate (94% <9 weeks, 81% ≥ 9 weeks, p=0.007).Differences in specificity were not seen (97% <9 weeks, 91% ≥ 9 weeks, p=0.228).No significant difference in specificity was found at any time point.

View Article: PubMed Central - PubMed

Affiliation: Department of Thoracic Surgery, Royal Victoria Hospital, Belfast.

ABSTRACT

Background: PET/CT scanning can determine suitability for curative therapy and inform decision making when considering radical therapy in patients with non-small cell lung cancer (NSCLC). Metastases to central mediastinal lymph nodes (N2) may alter such management decisions. We report a 2 year retrospective series assessing N2 lymph node staging accuracy with PET/CT compared to pathological analysis at surgery.

Methods: Patients with NSCLC attending our centre (excluding those who had induction chemotherapy) who had staging PET/CT scans and pathological nodal sampling between June 2006 and June 2008 were analysed. For each lymph node assessed pathologically, the corresponding PET/CT status was determined. 64 patients with 200 N2 lymph nodes were analysed.

Results: Sensitivity of PET/CT scans for indentifying involved N2 lymph nodes was 39%, specificity 96% and overall accuracy 90%. For individual lymph node analysis, logistic regression demonstrated a significant linear association between PET/CT sensitivity and time from scanning to surgery (p=0.031) but not for specificity and accuracy. Those scanned <9 weeks before pathological sampling were significantly more sensitive (64% >9 weeks, 0% ≥ 9 weeks, p=0.013) and more accurate (94% <9 weeks, 81% ≥ 9 weeks, p=0.007). Differences in specificity were not seen (97% <9 weeks, 91% ≥ 9 weeks, p=0.228). No significant difference in specificity was found at any time point.

Conclusions: We recommend that if a PET/CT scan is older than 9 weeks, and management would be altered by the presence of N2 nodes, re-staging of the mediastinum should be undertaken.

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Related in: MedlinePlus

An axial slice on A: CT, on B: attenuated corrected PET and on C: Fused PET/CT on a patient with a false negative pre-tracheal lymph node on PET. Although the CT image suggests nodal positivity by size criteria, the PET (region of interest denoted by red circle) does not demonstrate any significant uptake in this region. The enlarged node was positive at surgery.
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fig04: An axial slice on A: CT, on B: attenuated corrected PET and on C: Fused PET/CT on a patient with a false negative pre-tracheal lymph node on PET. Although the CT image suggests nodal positivity by size criteria, the PET (region of interest denoted by red circle) does not demonstrate any significant uptake in this region. The enlarged node was positive at surgery.

Mentions: The false negative rate was 10.9% with 7 out of 64 patients being incorrectly identified as having no N2 disease on the PET/CT. This may represent micrometastic disease present in small lymph nodes, whose small size are unlikely to be detected by PET/CT which has in our study are a resolution of 5mm slices. Central tumours with occult nodes on PET or could be related to lymph node size. In this study Pathological sampling commented on the presence of metastatic disease only and did not measure the size of the positive node to enable comparison to size on the pre-op PET scan. Furthermore, the reporting radiologist did not report the SUVMAX for those N2 nodes deemed negative on PET/CT. Hence it is not possible to assess the impact of nodal size and SUVMAX thresholds on the staging accuracy of PET/CT for N2 nodal stations. Positive N1 nodes on the basis of size or SUVMAX criteria did not affect the decision to proceed with radical surgery for these patients and therefore had no bearing on the staging accuracy or the likelihood to surgically sample N2 lymph nodes. Clearly a false negative rate is to be expected with the known potential of micro metastatic disease, particularly in adenocarcinoma. Figure 4 illustrates an example a false negative pre-tracheal lymph node which was positive at surgery.


The mediastinal staging accuracy of 18F-Fluorodeoxyglycose positron emission tomography/computed tomography in non-small cell lung cancer with variable time intervals to surgery.

Booth K, Hanna GG, McGonigle N, McManus KG, McGuigan J, O'Sullivan J, Lynch T, McAleese J - Ulster Med J (2013)

An axial slice on A: CT, on B: attenuated corrected PET and on C: Fused PET/CT on a patient with a false negative pre-tracheal lymph node on PET. Although the CT image suggests nodal positivity by size criteria, the PET (region of interest denoted by red circle) does not demonstrate any significant uptake in this region. The enlarged node was positive at surgery.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756862&req=5

fig04: An axial slice on A: CT, on B: attenuated corrected PET and on C: Fused PET/CT on a patient with a false negative pre-tracheal lymph node on PET. Although the CT image suggests nodal positivity by size criteria, the PET (region of interest denoted by red circle) does not demonstrate any significant uptake in this region. The enlarged node was positive at surgery.
Mentions: The false negative rate was 10.9% with 7 out of 64 patients being incorrectly identified as having no N2 disease on the PET/CT. This may represent micrometastic disease present in small lymph nodes, whose small size are unlikely to be detected by PET/CT which has in our study are a resolution of 5mm slices. Central tumours with occult nodes on PET or could be related to lymph node size. In this study Pathological sampling commented on the presence of metastatic disease only and did not measure the size of the positive node to enable comparison to size on the pre-op PET scan. Furthermore, the reporting radiologist did not report the SUVMAX for those N2 nodes deemed negative on PET/CT. Hence it is not possible to assess the impact of nodal size and SUVMAX thresholds on the staging accuracy of PET/CT for N2 nodal stations. Positive N1 nodes on the basis of size or SUVMAX criteria did not affect the decision to proceed with radical surgery for these patients and therefore had no bearing on the staging accuracy or the likelihood to surgically sample N2 lymph nodes. Clearly a false negative rate is to be expected with the known potential of micro metastatic disease, particularly in adenocarcinoma. Figure 4 illustrates an example a false negative pre-tracheal lymph node which was positive at surgery.

Bottom Line: Those scanned <9 weeks before pathological sampling were significantly more sensitive (64% >9 weeks, 0% ≥ 9 weeks, p=0.013) and more accurate (94% <9 weeks, 81% ≥ 9 weeks, p=0.007).Differences in specificity were not seen (97% <9 weeks, 91% ≥ 9 weeks, p=0.228).No significant difference in specificity was found at any time point.

View Article: PubMed Central - PubMed

Affiliation: Department of Thoracic Surgery, Royal Victoria Hospital, Belfast.

ABSTRACT

Background: PET/CT scanning can determine suitability for curative therapy and inform decision making when considering radical therapy in patients with non-small cell lung cancer (NSCLC). Metastases to central mediastinal lymph nodes (N2) may alter such management decisions. We report a 2 year retrospective series assessing N2 lymph node staging accuracy with PET/CT compared to pathological analysis at surgery.

Methods: Patients with NSCLC attending our centre (excluding those who had induction chemotherapy) who had staging PET/CT scans and pathological nodal sampling between June 2006 and June 2008 were analysed. For each lymph node assessed pathologically, the corresponding PET/CT status was determined. 64 patients with 200 N2 lymph nodes were analysed.

Results: Sensitivity of PET/CT scans for indentifying involved N2 lymph nodes was 39%, specificity 96% and overall accuracy 90%. For individual lymph node analysis, logistic regression demonstrated a significant linear association between PET/CT sensitivity and time from scanning to surgery (p=0.031) but not for specificity and accuracy. Those scanned <9 weeks before pathological sampling were significantly more sensitive (64% >9 weeks, 0% ≥ 9 weeks, p=0.013) and more accurate (94% <9 weeks, 81% ≥ 9 weeks, p=0.007). Differences in specificity were not seen (97% <9 weeks, 91% ≥ 9 weeks, p=0.228). No significant difference in specificity was found at any time point.

Conclusions: We recommend that if a PET/CT scan is older than 9 weeks, and management would be altered by the presence of N2 nodes, re-staging of the mediastinum should be undertaken.

Show MeSH
Related in: MedlinePlus