Thoracoscopic pleural cryobiopsy versus conventional forceps biopsy in diagnosis of exudative pleural effusion of unknown etiology

Diagnostic yields and safety of thoracoscopic cryobiopsies in Japan: A single-center retrospective observational study

BACKGROUND

Thoracoscopy is useful for diagnosing unexplained pleural effusions. A sufficient specimen volume is often difficult to obtain using forceps biopsies (FBs) but can be obtained with pleural cryobiopsies (CBs). This study aimed to assess the utility and safety of CB during thoracoscopy in the Japanese population.

METHODS

Patients who underwent thoracoscopic CBs at the Japanese Red Cross Medical Center between January 2017 and August 2023 were included in the study. Data were retrospectively analyzed, including clinical data, thoracoscopic findings, specimen size, diagnostic yield, and complications. The number of collected specimens and the freezing time were left to the discretion of the attending physician.

RESULTS

Twenty-six patients underwent thoracoscopic CB. Specimens obtained by CB were larger than those obtained by FB. Primary lung cancer was the most common cause of pleural effusion, followed by malignant pleural mesothelioma. CB contributed to the diagnosis in 24 of 26 cases (92.3%) and FB contributed to the diagnosis in 11 of 18 cases (61.1%). Severe fibrosis could be diagnosed in all 3 cases by CB, but not by FB. The common complications of CB included bleeding at the biopsy site and atelectasis, but no severe complications occurred.

CONCLUSIONS

The utility and safety of thoracoscopic CB for diagnosing pleural effusions in Japan were verified. The diagnostic yield, specimen size, and safety profile of CB support the diagnostic utility of this method.

Pleural effusion guidelines from ICS and NCCP Section 1: Basic principles, laboratory tests and pleural procedures

Pleural effusion is a common problem in our country, and most of these patients need invasive tests as they can't be evaluated by blood tests alone. The simplest of them is diagnostic pleural aspiration, and diagnostic techniques such as medical thoracoscopy are being performed more frequently than ever before. However, most physicians in India treat pleural effusion empirically, leading to delays in diagnosis, misdiagnosis and complications from wrong treatments. This situation must change, and the adoption of evidence-based protocols is urgently needed. Furthermore, the spectrum of pleural disease in India is different from that in the West, and yet Western guidelines and algorithms are used by Indian physicians. Therefore, India-specific consensus guidelines are needed. To fulfil this need, the Indian Chest Society and the National College of Chest Physicians; the premier societies for pulmonary physicians came together to create this National guideline. This document aims to provide evidence based recommendations on basic principles, initial assessment, diagnostic modalities and management of pleural effusions.

Efficacy and Safety of Pleural Cryobiopsy vs. Forceps Biopsy for Evaluation of Undiagnosed Pleural Effusion: A Systematic Review and Meta-Analysis

Background

Pleural cryobiopsy is a novel technique for the diagnosis of pleural pathologies. However, the safety and feasibility of this modality compared to standard forceps for pleural biopsy has not been fully elucidated. This systematic review and meta-analysis aims to establish the efficacy and safety of cryobiopsy for evaluation of undiagnosed pleural effusion.

Methods

For this systematic review and meta-analysis, we searched PubMed, Embase, Scopus, and Web of science databases up to December 16, 2021 to identify relevant articles. We included randomized controlled trials, cohort studies, retrospectives studies and case series that compared pleural cryobiopsy and forceps biopsy. A qualitative assessment was performed using the QUADAS-2 tool.

Results

Of the 365 articles identified by our search, 15 studies were eligible for inclusion. The specimen sizes obtained with cryobiopsy were significantly larger compared with forceps biopsy (Standard mean difference 1.16; 95 % CI: 0.51–1.82; P < 0.01). Furthermore, the cryobiopsy tissue specimens were deeper (OR 2.68; 95 % CI: 1.39–5.16; P < 0.01) and qualitatively better with less crush artifacts (OR 0.06; 95 % CI: 0.01–0.26; P < 0.01). There was no significant difference in diagnostic yield (OR 1.32; 95 % CI: 0.79–2.21; P = 0.29) and mild to moderate bleeding events (OR 1.21; 95 % CI: 0.64–2.29; P = 0.57) between pleural cryobiopsy and forceps biopsy. No publication bias was observed among these studies.

Conclusions

Compared to flexible forceps biopsy pleural cryobiopsy obtained larger and deeper tissue specimens with less crush artifacts but does not show superiority for diagnostic yield. Further studies are still needed to verify these findings.