Pleural Cryobiopsy A Systematic Review and Meta-Analysis

BACKGROUND: Pleural biopsy using either video-assisted thoracoscopic surgery or medical pleuroscopy is the current diagnostic criterion standard for pleural pathology with a high, yet imperfect, diagnostic yield. Cryobiopsy may provide greater tissue, increase depth of sampled tissue, and/or reduce crush artifact. However, its impact on diagnostic yield remains uncertain, and there are potential concerns regarding its safety too. We performed a systematic review and meta-analysis to investigate the same. METHODS: We performed a systematic search of MEDLINE, Embase, and Google Scholar for studies evaluating the performance of pleural cryobiopsy, assessing the quality of each study using the Quality Assessment, Data Abstraction and Synthesis-2 tool. Using inverse variance weighting, we performed a meta-analysis of diagnostic yield estimations. We also reviewed specimen characteristics and complications related to the procedure. RESULTS: Seven observational studies involving 586 pleural biopsies (311 cryobiopsies and 275 flexible forceps biopsies) were evaluated. All but one study used a semi-rigid thoracoscope. Meta-analysis generated a diagnostic yield of 96.5% for cryobiopsy and 93.1% for forceps biopsy with an inverse variance-weighted OR of 1.61 (95% CI, 0.71-3.66) and an I-2 of 16%. No instances of moderate to severe bleeding were reported with cryobiopsy. A funnel plot illustrated no major publication bias. CONCLUSIONS: Based on analysis of relatively homogenous observational data, pleural cryobiopsy is safe but does not increase diagnostic yield over flexible forceps biopsy. Adequately powered multicenter randomized trials are needed for further investigation.