Diagnostic value of the standardised uptake value (SUV) ratio of mediastinal lymph node to primary tumour in lung cancer.

PURPOSE

This study aimed to determine whether the mediastinal lymph node/tumour ratio (NTR) of the standardised uptake value (SUV) predicts N2 involvement more accurately than node SUV in patients with non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS

We retrospectively analysed consecutive patients with lung cancer at clinical stages I-IVA. All patients underwent positron emission tomography-computed tomography (PET-CT), followed by mediastinal staging using endobronchial ultrasound and endoscopic ultrasound imaging, and curative-intent lung resection with systematic lymph node dissection. Pathological examination of the surgical specimen was performed for confirmation.

RESULTS

The data from 774 patients were analysed. There was a significant correlation between the risk of false-negative PET results for N2 disease and both the SUV of the mediastinal nodes ( = 0.012) and NTR ( = 0.030). The NTR outperformed node SUV in predictive ability; the Akaike information criterion was 307.268 for NTR compared to 308.498 for node SUV. Three factors were significantly associated with the positive predictive value of PET: patient age ( = 0.021), female sex ( = 0.012), and adenocarcinoma histology ( = 0.036). There were no significant correlations between PET sensitivity, specificity, and negative predictive value (NPV), and age, sex, body mass index (BMI), tumour grade, lobar location, or histological type.

CONCLUSIONS

The NTR may be a useful tool for excluding N2 disease in NSCLC. PET sensitivity and NPV for detecting N2 disease are not influenced by age, sex, BMI, tumour grade, lobar location, or histological type.