Mediastinal Endobronchial Ultrasound Bronchoscopy Cryobiopsy Study In Sweden

Endobronchial ultrasound bronchoscopy (EBUS) is an established method for sampling of mediastinal and hilar lymph nodes and masses. Cytology specimens can be obtained with transbronchial needle aspiration (EBUS TBNA), and this is a valuable tool in the diagnostic work up of lesions adjacent to central airways and in the staging of lung cancer. EBUS TBNA is a robust method that shows excellent results in diagnosing lung cancer cases with a reported diagnostic yield up to 90% from multiple studies. EBUS TBNA is a safe procedure with reported complications in 1,2 - 3,6% of cases.

In clinical situations where non-malignant diseases (e.g. sarcoidosis, tuberculosis) or malignancies other than lung cancer (e.g. lymphoma) affect the mediastinum is the efficacy of EBUS TBNA relatively limited and these cases often require histopathological evaluation rather than cytological assessment.

EBUS TBMCB (EndoBronchial UltraSound TransBronchial Mediastinal CryoBiopsy) is a novel method of obtaining cryobiopsies for histopathology from mediastinal lesions, which has previously not been possible with endobronchial procedures. This method is becoming more utilised internationally after the publication of the first studies examining its safety and efficacy. In the last couple of years has EBUS TBMCB been evaluated in two randomized studies from the same study group and a few observational studies where adding EBUS TBMCB to EBUS TBNA showed an increase in diagnostic yield without adding significant adverse events. The sensitivity of EBUS TBMCB were similar to that of EBUS TBNA in cases of lung cancer but there was found, in all studies, a significant increase of diagnostic yield in cases of non-malignant diseases and metastases from extra thoracic tumours.

There are however some aspects of this novel method yet not studied like the number of biopsies needed from a lesion to collect adequate material for histopathological evaluation. At the thoracic oncology diagnostics units at Skåne University Hospital and Umeå University hospital, EBUS TBMCB has been introduced in clinical practice, performed by experienced bronchoscopists. In recognition of the need for further clarification regarding several aspects of this novel method the investigators plan to collect data prospectively and systematically from EBUS TBMCB procedures.

Our study is a prospective observational non-randomized clinical trial where all the patients undergo the same procedure and every patient's own samples are compared to each other. The investigators conduct EBUS TBNA and EBUS TBMCB to all the study participants and the investigators are numbering the cryobiopsy samples to evaluate the number of biopsies needed to reach a definite diagnosis and to assess the added value of every sample taken from the same patient. Every participitant's own samples are compared to each other and added value of EBUS TBMCB is defined as the difference in diagnostic yield between the EBUS TBNA alone and the combination of EBUS TBNA with EBUS TBMCB. Diagnostic yield is defined as the efficacy of the investigation module in reaching a definite diagnosis (percentage of cases with a definite diagnosis).