The size of mediastinal lymph nodes and its relation with metastatic involvement: a meta-analysis

Abstract

Positron emission tomography with 18-fluorodeoxyglucose (FDG-PET) seems to be superior to computed tomography (CT) in staging the mediastinum in patients with non-small-cell lung cancer (NSCLC). However, recent results suggest that FDG-PET performance characteristics are conditional for nodal size as shown by CT: FDG-PET is more sensitive but less specific with lymph node enlargement on CT. The association between size and the probability of malignancy needs to be known to predict the post-test probabilities after PET, and finally, stratify patients for mediastinoscopy or thoracotomy depending on the PET and CT results. Therefore, we performed a meta-analysis of available studies reporting on the prevalence of metastatic involvement for different size categories of enlarged lymph nodes in patients with NSCLC and were able to include 14 studies. The prevalence of metastatic involvement and conditional test performance of CT and FDG-PET were calculated for lymph nodes measuring 10-15 mm, 16-20 mm and >20 mm. We found a post-test probability for N2 disease of 5% for lymph nodes measuring 10-15 mm on CT in patients with a negative FDG-PET result, suggesting that these patients should be planned for thoracotomy because the yield of mediastinoscopy will be extremely low. For patients with lymph nodes measuring > or =16 mm on CT and a negative FDG-PET result a post-test probability for N2 disease of 21% was found, suggesting that these patients should be planned for mediastinoscopy prior to possible thoracotomy to prevent too many unnecessary thoracotomies in this subset.

Effectiveness and safety of endobronchial ultrasound-transbronchial needle aspiration: a systematic review

“…In a meta-analysis comparing PET with CT scanning for mediastinal staging, the prevalence of malignant lymph nodes was 37% [33]. In another recent meta-analysis comparing PET and CT scanning, the post-test probability for N2 disease was found to be 5% for lymph nodes measuring 10-15 mm on CT and 21% for lymph nodes measuring o16 mm, when patients had a negative FDG-PET [35]. Even though prevalence can be highly dependent on the pre-tests carried out in combination with CT (post-test probability of 62% with FDG-PET), it must be acknowledged that recruiting of patients with a high probability of suffering from the disease, of severe cases or of cases with appreciable enlargement of the lymph glands (.2 cm) can lead to an increase in sensitivity and PPV.…”

Segmentation Based Features for Lymph Node Detection from 3-D Chest CT

“…The classifiers were only trained on lymph nodes that have a minimum size of 10mm in at least two dimensions. Smaller lymph nodes are usually not pathologic [10] and were therefore neglected. Among the segmented lymph nodes, 289 were used for training.…”

CT differentiation of enlarged mediastinal lymph node due to anthracosis from metastatic lymphadenopathy: a comparative study proven by endobronchial US-guided transbronchial needle aspiration

“…Most often a coherent appearance of malignancy and enlarged lymph nodes was demonstrated on CT (8,9). Usually a short axis diameter > 1 cm is considered as the standard threshold for a suspicious lymph node, but metastases have been found in up to 20% of small nodes in patients with clinical stage cT1N0 and cT2N0, and only about 50% of the nodes with a diameter of 1.5 cm to 2 cm are metastatic (3).…”