Combo of cryobiopsy and EBUS-TBNA improves diagnostic yield for mediastinal lesions: The LANCET

CHINA: A study published in the LANCET, Respiratory Medicine mentioned adding mediastinal cryobiopsy to standard Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) improves the diagnostic yield for mediastinal lesions. This has a good safety profile and is a useful diagnostic tool for mediastinal diseases.

EBUS-TBNA is used in lung cancer for mediastinal nodal staging. It is an initial investigatory technique, but this consideration may have some limitations. The diagnostic yield in mediastinal lesions may get restricted due to the inadequacy of intact tissues. This is the limitation encountered in mediastinal lesions of specific aetiologies.

A study by Zhang et al. has concluded that the diagnostic yield in such cases could be achieved with safety and validity in performing transbronchial cryobiopsy under EBUS guidance. The results were evaluated in 197 patients with a diagnostic yield of 79.9% and 91.8% for TBNA and transbronchial mediastinal cryobiopsy, respectively and a significant p-value of 0.001.

The researchers of the same study said that EBUS-guided transbronchial mediastinal cryobiopsy provides intact samples with greater volume. The approach increases the yield of histological samples for diagnosing mediastinal lesions.

Considering this, research was conducted by a team led by Dr Ye Fan from the Department of Respiratory Diseases at Xinqiao Hospital with the aim of the team to evaluate the safety profile of the approach and also determining the effectiveness of combined use of transbronchial mediastinal cryobiopsy and EBUS-TBNA (standard) to improve diagnostic yield for the diagnosis of the mediastinal disease.

The critical points of the study are:

• The trial was conducted in Europe and Asia at three hospital sites. (12 Oct 2020 - 9 Sept 2021)

• Patients were aged 15 years or older.

• Patients included in the study had one mediastinal lesion at least 1 cm or longer in the short axis. Diagnostic bronchoscopy was required.

• There were two groups in the study: combined and control

• EBUS-TBNA and transbronchial mediastinal cryobiopsy was the combined group and had 136 patients.

• EBUS-TBNA alone was the control group and had 135 patients.

• Participants were randomly assigned to a ratio of 1:1. A total of 271 patients were enrolled.

• Neither participants nor investigators, due to the nature of the intervention, were masked to group assignment

• The differences in complications and diagnostic yield were the coprimary outcomes.

• There was an increase in overall diagnostic yield on cryobiopsy in addition to standard sampling.

• The interindividual results (combined vs control) were 93% vs 81%.

• The risk ratio [RR] was 1·15, and the p-value was 0·0039, which was significant.

• The intraindividual findings were 94 % vs 82 % with RR of 1·15 and p-value of 0·0026.

• In subgroup analyses (intraindividual population), diagnostic yields were similar for mediastinal metastasis, combined group vs control group was 99% vs 99% with RR of 1·00 and p-value of 1·00.

• There was more sensitivity in the combined approach than standard needle aspiration in benign disorders (94% vs 67%); RR was 1·41 with p=0·0009.

• The combined approach improved the tissue sample's suitability for molecular and immunological analyses of non-small-cell lung cancer.

• There was no difference in the incidence of adverse events, biopsy-related, between trial groups.

• Grade 3–4 airway bleeding was reported in 2% of patients combined and 1% of the control group with RR of 0·67 and p=1·0.

• None of the complications were severe, causing death and disability.

The co-researcher, Dr Zhang from the Department of Oncology at Xinqiao Hospital, added an interpretation that mediastinal cryobiopsy addition to standard EBUS-TBNA improves diagnostic yield for mediastinal lesions. The approach is safe and considered a "valid first-line" diagnostic tool for mediastinal diseases.

The study was funded by the National Natural Science Foundation of China, as acknowledged.

Further reading:

Transbronchial needle aspiration combined with cryobiopsy in the diagnosis of mediastinal diseases: a multicentre, open-label, randomised trial. Fan et al.