Diagnostic Performance of 18F-FDG PET/CT for Lymph Node Staging in Patients with Operable Non-small-cell Lung Cancer and Inflammatory Lung Disease

Abstract

As 18 F-fluorodeoxyglucose (FDG) is taken up by inflammatory lymph nodes, it could be falsely interpreted as metastasis. Therefore, we evaluated the diagnostic ability of positron emission tomography/computed tomography (PET/CT) for lymph node staging of lung cancer when inflammatory lung disease coexisted. Patients with operable non-small-cell lung cancer and FDG-avid lymph nodes were retrospectively classified into two groups; those with inflammatory lung disease (ILD) and those without it (NILD). Receiver operating characteristic (ROC) curve analysis was performed for maximum standardized uptake value (SUVmax), pattern of FDG uptake, maximum Hounsfield unit, and size, and then the areas under the ROC curves (AUCs) were compared between subgroups. There were 124 patients (ILD/ NILD = 38/86) and 396 FDG-avid lymph nodes (ILD/ NILD = 140/256). The average number of FDG-avid lymph nodes was greater in ILD (3.7 vs. 2.9, p = 0.039), whereas the proportion of metastasis was higher in NILD (25.4% vs. 11.4%, p = 0.002). With all N1-N3 lymph nodes and the NILD group, the AUC values of all four parameters were significantly greater than 0.5 (p \ 0.05), and SUVmax was the most valuable parameter for lymph node metastasis. However, in the ILD group, only the AUC value of SUVmax was significantly greater than 0.5. These results were reproduced when analyses were performed with N1-N2 lymph nodes. In conclusion, SUVmax was the most valuable PET/CT parameter for assessment of lymph node metastasis in patients with operable non-small-cell lung cancer. In addition, it was the only valuable parameter when inflammatory lung disease coexisted.

Differential diagnosis between 18F-FDG-avid metastatic lymph nodes in non-small cell lung cancer and benign nodes on dual-time point PET/CT scan

“…FDG-avid silicotic nodule in the right lung was also seen on both scans (arrowheads) NSCLC, with the average sensitivity and specificity of approximately 80 and 90%, respectively [2-5, 10, 20-23]. However, as seen in the present study, the further accumulated experiences showed that non-metastatic, inflammatory LNs showed false-positive FDG uptake on a single scan, especially in a geographic region with patients at high risk of granulomatous or infectious diseases [6][7][8][9][10]. A longterm smoking history induces lymphoid follicular hyperplasia in LNs and also causes false-positive FDG uptake [24].…”

“…Since Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) is superior to morphologic computed tomography (CT) in the evaluation of LN status in patients with NSCLC, this technique has been increasingly used [2][3][4][5]. Although LN status has been interpreted qualitatively or quantitatively on a single PET scan, based on the general tendency of a higher FDG uptake in metastatic LNs than in non-metastatic LNs [2][3][4][5], the recent studies showed the limitation of this technique due to hypermetabolic LNs associated with pulmonary infectious or granulomatous diseases [6][7][8][9][10][11]. These hypermetabolic benign LNs causing false-positive results coexist in patients with NSCLC and may be a critical problem for management of these patients.…”

Value of Dual-Time-Point FDG PET/CT for Mediastinal Nodal Staging in Non-Small-Cell Lung Cancer Patients With Lung Comorbidity

“…Despite FDG PET/CT scans have shown high sensitivity, specificity, and accuracy for mediastinal LN metastases in NSCLC, still there are a proportion of patients who are inaccurately staged because of the false positives and false negatives. [11][12][13][14] Studies showed that the diagnostic performance FDG PET/CT for mediastinal LN staging in lung cancer was lower in patients with inflammatory lung disease. 13,14 Therefore, we classified our patients into 2 groups based on the presence of pulmonary comorbidity on chest CT or PET/CT images.…”

Update on nodal staging in non-small cell lung cancer with integrated positron emission tomography/computed tomography: a meta-analysis

“…1. Data were analyzed based on node [4,18,28,33,34,36,37,[42][43][44], patient [21-24, 29, 30, 35, 38, 39], or both [19, 20, 25-27, 31, 32, 40, 41] in each study. The summary of studies included is presented in Table 1.…”