Clinical effectiveness and cost-effectiveness of endobronchial and endoscopic ultrasound relative to surgical staging in potentially resectable lung cancer: results from the ASTER randomised controlled trial

Abstract

Objective: To assess the clinical effectiveness and cost-effectiveness of endosonography (followed by surgical staging if endosonography was negative), compared with standard surgical staging alone, in patients with non-small cell lung cancer (NSCLC) who are otherwise candidates for surgery with curative intent. Design: A prospective, international, open-label, randomised controlled study, with a trialbased economic analysis. Setting: Four centres: Ghent University Hospital, Belgium; Leuven University Hospitals,Belgium; Leiden University Medical Centre, the Netherlands; and Papworth Hospital, UK. Participants: Inclusion criteria: known/suspected NSCLC, with suspected mediastinal lymph node involvement; otherwise eligible for surgery with curative intent; clinically fit for endosonography and surgery; and no evidence of metastatic disease. Exclusion criteria: previous lung cancer treatment; concurrent malignancy; uncorrected coagulopathy; and not suitable for surgical staging. Interventions: Study patients were randomised to either surgical staging alone (n = 118) or endosonography followed by surgical staging if endosonography was negative (n = 123). Endosonography diagnostic strategy used endoscopic ultrasound-guided fine-needle aspiration combined with endobronchial ultrasound-guided transbronchial needle aspiration, followed by surgical staging if these tests were negative. Patients with no evidence of mediastinal metastases or tumour invasion were referred for surgery with curative intent. If evidence of malignancy was found, patients were referred for chemoradiotherapy. Main outcome measures: The main clinical outcomes were sensitivity (positive diagnostic test/nodal involvement during any diagnostic test or thoracotomy) and negative predictive value (NPV) of each diagnostic strategy for the detection of N2/N3 metastases, unnecessary thoracotomy and complication rates. The primary economic outcome was cost–utility of the endosonography strategy compared with surgical staging alone, up to 6 months after randomisation, from a UK NHS perspective. Results: Clinical and resource-use data were available for all 241 patients, and complete utilities were available for 144. Sensitivity for detecting N2/N3 metastases was 79% [41/52; 95% confidence interval (CI) 66% to 88%] for the surgical arm compared with 94% (62/66; 95% CI 85% to 98%) for the endosonography strategy (p = 0.02). Corresponding NPVs were 86% (66/77; 95% CI 76% to 92%) and 93% (57/61; 95% CI 84% to 97%; p = 0.26). There were 21/118 (18%) unnecessary thoracotomies in the surgical arm compared with 9/123 (7%) in the endosonography arm (p = 0.02). Complications occurred in 7/118 (6%) in the surgical arm and 6/123 (5%) in the endosonography arm (p = 0.78): one pneumothorax related to endosonography and 12 complications related to surgical staging. Patients in the endosonography arm had greater EQ-5D (European Quality of Life-5 Dimensions) utility at the end of staging (0.117; 95% CI 0.042 to 0.192; p = 0.003). There were no other significant differences in utility. The main difference in resource use was the number of thoracotomies: 66% patients in the surgical arm compared with 53% in the endosonography arm. Resource use was similar between the groups in all other items. The 6-month cost of the endosonography strategy was £9713 (95% CI £7209 to £13,307) per patient versus £10,459 (£7732 to £13,890) for the surgical arm, mean difference £746 (95% CI –£756 to £2494). The mean difference in quality-adjusted life-year was 0.015 (95% CI –0.023 to 0.052) in favour of endosonography, so this strategy was cheaper and more effective. Conclusions: Endosonography (followed by surgical staging if negative) had higher sensitivity and NPVs, resulted in fewer unnecessary thoracotomies and better quality of life during staging, and was slightly more effective and less expensive than surgical staging alone. Future work could investigate the need for confirmatory mediastinoscopy following negative endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), the diagnostic accuracy of EUS-FNA or EBUS-TBNA separately and the delivery of both EUSFNA or EBUS-TBNA by suitably trained chest physicians.