Introduction Isolated mediastinal lymphadenopathy (IML) is a common presentation to respiratory physicians and mediastinoscopy is traditionally considered the gold-standard investigation when a pathological diagnosis is required. EBUS-TBNA is established as an alternative to mediastinoscopy in patients with lung cancer. However, the utility and healthcare costs of EBUS-TBNA in patients with IML is unknown.
Methods This prospective clinical trial recruited 77 consecutive patients with IML who were referred for mediastinoscopy from five centres between April 2009 and March 2011. All patients underwent EBUS-TBNA. If the results from EBUS-TBNA were not conclusive, patients underwent mediastinoscopy. The co-primary endpoints were the proportion of mediastinoscopies saved and NHS costs. The Bonferroni correction was applied to the type 1 error to account for multiple significance testing. Economic evaluation of the EBUS-TBNA strategy (where negative EBUS-TBNA is followed by mediastinoscopy) vs mediastinoscopy alone from an NHS perspective was carried out using a decision tree model and univariate threshold sensitivity analysis.
Results EBUS-TBNA prevented 87% of mediastinoscopies (97.5% CI 78 to 96%, p<0.001) but failed to provide a diagnosis in 10 patients, all of whom underwent mediastinoscopy (Abstract S56 figure 1). Mediastinoscopy provided a specific diagnosis in 6 cases while the remaining four patients had clinical and radiological follow-up of at least 6 months duration. The sensitivity and negative predictive value of EBUS-TBNA in patients with IML was 92% (95% CI 83 to 95) and 40% (95% CI 12% to 74%) respectively. No significant complications of EBUS-TBNA or mediastinoscopy were observed. The patients included in the trial were similar to a historical control group of 68 patients with IML undergoing mediastinoscopy in 2008. The cost of the EBUS-TBNA strategy was £1871 per patient while a strategy of mediastinoscopy alone was £3268 per patient (p<0.001). Threshold sensitivity analysis demonstrated that the EBUS-TBNA strategy was less costly than mediastinoscopy if the cost per EBUS-TBNA procedure was <£2828.
Conclusions EBUS-TBNA is a safe, highly sensitive and cost-saving initial investigation in patients with IML being referred for mediastinoscopy. The low negative predictive value of EBUS-TBNA in this setting indicates that mediastinoscopy should be performed in cases of negative EBUS-TBNA.
Trial registration clinicaltrials.gov NCT00932854.