Positive pleural cytology is an indicator for visceral pleural invasion in metastatic pleural effusions

Our plain-English summary of Positive pleural cytology is an indicator for visceral pleural invasion in metastatic pleural effusions, by M.E. Froudarakis, J. Plojoux, E. Kaspi, et al (The Clinical Respiratory Journal, 2018).

The study

• Authors: M.E. Froudarakis, J. Plojoux, E. Kaspi, S. Anevlavis, S. Laroumagne, G. Karpathiou, E. Roca, D. Adler, H. Dutau, P. Astoul
• Journal: The Clinical Respiratory Journal
• Published: 2018;12(3):1011-1016
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: In case of undiagnosed pleural effusions, it is necessary to conduct thoracentesis with pleural fluid (PF) cytology. Yet, sensitivity of PF cytology is widely variable as a result of sample size, experience, and preparation method.

Objectives: The aim of this study was to assess whether pleural fluid (PF) cytology is correlated to visceral or parietal pleural invasion as assessed by thoracoscopy in metastatic pleural effusions.

Methods: All records of patients with pleural effusion were reviewed. The inclusion criteria were as follows: PF cytology, reported appearance of macroscopic pleural invasion during thoracoscopy and malignant diagnosis. Patients with mesothelioma were excluded. Finally, 287 patients who met all criteria were selected. According to the thoracoscopy findings, the extent of the disease on the pleura was analyzed in relation to the PF cytology.

Results: In this study, 160 patients (55.7%) had a positive PF cytology (Group A) while 127 (44.3%) recorded negative PF cytology (Group B). From Group A, patients with visceral pleural invasion were 120 (75%) while only 49 patients (38.5%) were found from Group B and the difference was statistically significant (P < .00001). In univariate analysis, visceral pleural invasion was strongly associated with positive PF cytology (P < .001). Other significant associations with positive PF cytology included PF bloody aspect (P = .012), and endoscopic mixed pattern of pleural invasion (P = .0039). Only visceral pleural invasion was statistically significant in multivariate analysis (P < .001).

Conclusions: In patients with pleural metastatic disease, visceral pleural invasion is the only significant factor associated with positive pleural fluid cytology.

© 2017 John Wiley & Sons Ltd.

In plain English

This study does not examine asbestos exposure, and patients with mesothelioma were excluded. It was a retrospective study of 287 patients whose pleural effusion (fluid around the lung) was caused by cancer that had spread from elsewhere. Patients were treated at hospitals in Marseille, France, and Alexandroupolis, Greece, between 2011 and 2013. The authors compared the results of fluid cytology (looking for cancer cells in drained fluid) with what was seen at thoracoscopy, a camera examination of the chest cavity. Cytology was positive in 160 patients (55.7%) and negative in 127 (44.3%). Cancer on the visceral pleura, the lining covering the lung, was seen in 120 (75%) of the positive-cytology group and 49 (38.5%) of the negative-cytology group. Cancer on the parietal pleura, the lining of the chest wall, was found in 97% of patients and did not differ between groups. In multivariate analysis, visceral pleural invasion was the only independent factor (odds ratio 13.38). The authors concluded that cytology yield might be related to visceral pleural invasion. They noted their mixed patient population as a limitation.

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 study of patient records from two centres
• Who was studied: 287 patients with malignant pleural effusion from metastatic cancer, with cytology before thoracoscopy and a cancer diagnosis confirmed by biopsy. 158 were from Marseille, France, and 129 from Alexandroupolis, Greece, seen between January 1st 2011 and December 31st 2013. Patients with malignant pleural mesothelioma were excluded. The most frequent cancers were non-small cell lung cancer (151) and breast cancer (61).
• Exposure: Not applicable: the article does not study asbestos or any fiber exposure. The factor examined was the pattern of pleural invasion seen at thoracoscopy, compared with pleural fluid cytology results.
• Main results:
  • 160 patients (55.7%) had positive pleural fluid cytology (Group A) and 127 (44.3%) had negative cytology (Group B)
  • Visceral pleural invasion was seen in 120 patients (75%) of Group A and 49 patients (38.5%) of Group B; the difference was statistically significant (p less than 0.00001)
  • Parietal pleural invasion was found in 278 patients (97%) overall, with no difference between the two groups (p=0.307)
  • In univariate analysis, visceral pleural invasion was associated with positive cytology (odds ratio 10.6, 95% CI 6.06 to 18.39, p less than 0.001)
  • Bloody fluid was associated with positive cytology (p=0.012), as was a mixed endoscopic pattern of invasion (p=0.0039)
  • The positive and negative cytology groups also differed in age (p=0.028), gender (p=0.003) and primary cancer origin (p=0.032)
  • In multivariate analysis, visceral pleural invasion was the only independent factor predicting positive cytology (odds ratio 13.38, p less than 0.001)
• The authors' conclusion: The authors concluded that in metastatic pleural effusion, the diagnostic yield of fluid cytology might be related to invasion of the visceral pleura seen at thoracoscopy. They suggested this may partly explain the variation in cytology yield reported in the literature.
• Limitations the authors state:
  • The patient population was heterogeneous; the authors said confirmatory studies are needed in specific groups such as breast or lung cancer patients
  • The data analysis was retrospective, although the data came from records filled in prospectively

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: Cytology, Pleural Effusion, Thoracentesis, Thoracoscopy, Mesothelioma, Pleura, Multivariate Analysis, Fluid Cytology.

Related studies

• Pleural fluid cytological yield and visceral pleural invasion in patients with epithelioid malignant pleural mesothelioma — V. Pinelli, S. Laroumagne, et al. (2012)
• Pleural small cell carcinoma with massive pleural effusion: A case report — J.G. Jang, M.H. Jang, et al. (2019)
• Catheter Tract Metastasis in Mesothelioma Patients with Indwelling Pleural Catheters: A Retrospective Cohort Study — M.A. Mitchell, P. Li, et al. (2019)
• Prognostic factors in patients presenting with pleural effusion revealing malignancy — S. Anevlavis, G. Kouliatsis, et al. (2014)
• The long-term morbidity of pleuroperitoneal shunts in the management of recurrent malignant effusions — O. Genc, M. Petrou, et al. (2000)
• Defect in recruiting effector memory CD8+ T-cells in malignant pleural effusions compared to normal pleural fluid — A. Scherpereel, B.D. Grigoriu, et al. (2013)

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