Diagnostic validity of combined transbronchial and transoesophageal ultrasound in positron emission tomography node-negative lung cancer.

AIM: The role of invasive mediastinal diagnostic methods in lung cancer with negative positron emission tomography (PET) remains unclear. This study aimed to determine the sensitivity and negative predictive value (NPV) of combined endobronchial ultrasound (EBUS) and endoscopic ultrasound (EUS), referred to as combined ultrasound (CUS), for diagnosing N2 disease in this group of patients.

MATERIALS AND

METHODS

single-centre study analysing medical records of clinical stage I to IVA lung cancer patients was conducted. All patients underwent positron emission tomography computed tomography (PET-CT), followed by CUS imaging and lung resection with systematic lymph node dissection. Pathological examination of lymph nodes was the reference standard.

RESULTS

Data from 596 patients were analysed. The prevalence of N2 disease was 8%. The sensitivity, specificity, and the NPV of CUS in detecting N2 disease were 14%, 98%, and 93%, respectively. Sensitivity and NPV were not significantly associated with age, sex, body mass index (BMI), tumour grade, lobar location, or histological type (P > 0.05). Minimal N2 disease was found in 37 of 43 patients with negative CUS results; only 6 of 596 patients had more than minimal (N2b) disease missed by CUS. The NPV for minimal N2 involvement was 98%.

CONCLUSION

In PET-negative mediastinal lymph nodes, N2 disease prevalence is low. CUS has an NPV of 93% for N2 disease and 98% for more than minimal N2 involvement. The diagnostic yield of CUS is unaffected by clinical characteristics, making it a reliable method for ruling out significant N2 disease in PET-negative patients and potentially reducing the need for more invasive procedures.