Cryobiopsy during flex-rigid pleuroscopy: an emerging alternative biopsy method in malignant pleural mesothelioma. A comparative study of pathology

Our plain-English summary of Cryobiopsy during flex-rigid pleuroscopy: an emerging alternative biopsy method in malignant pleural mesothelioma. A comparative study of pathology, by T. Nakai, Y. Matsumoto, S. Sasada, et al (Japanese Journal of Clinical Oncology, 2019).

The study

• Authors: T. Nakai, Y. Matsumoto, S. Sasada, M. Tanaka, T. Tsuchida, Y. Ohe, N. Motoi
• Journal: Japanese Journal of Clinical Oncology
• Published: 2019;49(6):559-566
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Malignant pleural mesothelioma (MPM) is rarely an asbestos-related cancer with a poor prognosis that is difficult to distinguish from some benign conditions by using conventional biopsy techniques. The purpose of this study was to evaluate the utility of a novel biopsy technique using a cryoprobe during flex-rigid pleuroscopy for diagnosing MPM.

Methods: Consecutive patients who underwent pleural cryobiopsy during flex-rigid pleuroscopy from June through November 2017 to diagnose the cause of pleural effusion were collected. From these, cases ultimately diagnosed as MPM were selected. Pleural biopsies were performed by using conventional instruments followed by a cryoprobe. The obtained samples were histologically examined and compared with regard to the quality (sample size, tissue depth, and crush rate), immunohistochemical (IHC) staining, and p16 by fluorescence in situ hybridization (FISH).

Results: In total, five patients ultimately diagnosed as MPM were enrolled. The sample collected was significantly larger for cryobiopsy than conventional biopsy (18.9 mm2 vs. 6.7 mm2, P < 0.001). Full-thickness biopsies were achieved in four cases by using cryobiopsy compared with one case by conventional biopsy. Moreover, the crush rate was significantly less for cryobiopsy than conventional biopsy (9% vs. 35%, P < 0.001). The results of IHC staining and p16 by FISH were similar between biopsy techniques. Cryobiopsy successfully led to accurate diagnosis of MPM in all cases, whereas conventional biopsy was diagnostic in one case. No severe complications developed after either biopsy technique.

Conclusion: Cryobiopsy during flex-rigid pleuroscopy is a feasible and convenient biopsy technique that supports precise diagnosis of MPM.

© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: [email protected].

In plain English

This small retrospective study, from a single cancer hospital in Tokyo, compared two ways of taking tissue from the chest lining (pleura) during flex-rigid pleuroscopy, a camera procedure done under local anesthesia. Of 14 patients who had cryobiopsy (a frozen probe tip that sticks to tissue and pulls it out) from June through November 2017, the five later diagnosed with malignant pleural mesothelioma were studied. All five were men with a history of asbestos exposure. Each had conventional biopsies first, then cryobiopsies from the same sites. Cryobiopsy samples were larger (median 18.9 versus 6.7 square millimetres) and less crushed (median 9% versus 35%). In four patients, cryobiopsy reached deeper tissue showing tumor invasion into fat. Cryobiopsy samples allowed a mesothelioma diagnosis in all five patients. Conventional samples did so in one. Staining and p16 gene test results were nearly identical between the methods. Cryobiopsy caused mild pain in two patients and mild bleeding in one. The authors concluded that cryobiopsy is feasible and convenient. They noted that five cases show only feasibility and that benign conditions could not be assessed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective, single-center study comparing conventional pleural biopsy with cryobiopsy taken from the same sites in the same patients
• Who was studied: Five patients diagnosed with malignant pleural mesothelioma. They were selected from 14 consecutive patients who had pleural cryobiopsy during flex-rigid pleuroscopy for pleural effusion at the National Cancer Center Hospital, Tokyo, from June through November 2017. The other nine patients were diagnosed with primary lung cancer. All five were men, aged 58 to 75.
• Exposure: The study compared biopsy techniques: a cryoprobe versus conventional instruments (standard flexible forceps, or an insulated-tip diathermic knife-2). It did not study asbestos exposure itself. All patients had histories of asbestos exposure, but no fiber types, jobs or doses are given.
• Main results:
  • Sample size was significantly larger for cryobiopsy than for conventional biopsy: median 18.9 versus 6.7 square millimetres, P less than 0.001.
  • Crush rate was significantly lower for cryobiopsy than for conventional biopsy: median 9% versus 35%, P less than 0.001.
  • Cryobiopsy obtained deeper tissue showing tumor cell invasion in four of the five cases.
  • Conventional biopsy obtained deeper tissue in one case, but crush artifacts meant tumor invasion could not be confirmed.
  • All five cases could be diagnosed as malignant pleural mesothelioma from cryobiopsy samples: three epithelioid, one biphasic and one sarcomatoid.
  • Only one case was definitively diagnosed as malignant pleural mesothelioma from conventional biopsy samples.
  • Immunohistochemical staining and p16 deletion (FISH) results were nearly identical between the two techniques.
  • Conventional biopsy caused no complications. Cryobiopsy caused mild self-limiting pain in two patients and mild bleeding in one patient.
  • In this series, a cryobiopsy took about 1 minute to complete, compared with about 10 minutes for a biopsy using the insulated-tip knife.
• The authors' conclusion: The authors concluded that pleural cryobiopsy during flex-rigid pleuroscopy is a feasible and convenient biopsy technique for precise diagnosis of malignant pleural mesothelioma.
• Limitations the authors state:
  • The study was retrospective and done at a single cancer center, which increases the likelihood of selection bias.
  • The diagnostic value of cryobiopsy for benign conditions could not be evaluated.
  • With only five cases, the study shows only that the technique is feasible.
  • Complications might become more frequent as more cases are done.
  • The comparison of the insulated-tip knife-2 with the cryoprobe was limited.
  • The effect of freezing time on sample quality and complication rates was not evaluated.
  • The usefulness of cryobiopsy for diagnosing desmoplastic malignant pleural mesothelioma was not evaluated.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Biopsy, Pleural Mesothelioma, Pathology, Prognosis, Pleural Effusion, Fluorescence In Situ Hybridization (FISH).

Related studies

• Flex-rigid pleuroscopy under local anesthesia in patients with dry pleural dissemination on radiography — Y. Watanabe, S. Sasada, et al. (2014)
• Use of cryobiopsy during pleuroscopy for diagnosis of sarcomatoid malignant mesothelioma — H.P. Chan, M.F. Liew, et al. (2017)
• Semi-Rigid Thoracoscopic Punch Biopsy Using a Hybrid Knife with a High-Pressure Water Jet for the Diagnosis of Pleural Effusions — Y. Yin, R. Eberhardt, et al. (2016)
• Flex-rigid pleuroscopic biopsy with the SB knife Jr is a novel technique for diagnosis of malignant or benign fibrothorax — X.B. Wang, Y. Yin, et al. (2016)
• Rigid Mini-Thoracoscopy: The New Kid on the Block — E.O. Bedawi, N.M. Rahman (2020)
• An electrocautery pleural biopsy for the diagnosis of desmoplastic malignant mesothelioma during semirigid thoracoscopy — S. Sasada, K. Kawahara, et al. (2008)

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