Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging

Our plain-English summary of Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging, by R.T. Ripley, N. Palivela, S.S. Groth, et al (The Annals of Thoracic Surgery, 2021).

The study

• Authors: R.T. Ripley, N. Palivela, S.S. Groth, E.A. Choi, L.D. Cornwell, P.W. Carrott, G. Van Buren, T.G. Splawn, D.J. Sugarbaker, B.M. Burt
• Journal: The Annals of Thoracic Surgery
• Published: 2021;112(5):1568-1574
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: With a multimodal treatment strategy, cytoreductive surgery extends survival in malignant pleural mesothelioma. Improving the accuracy of staging can refine patient selection. Our objective was to determine whether diagnostic laparoscopy (DL) improves staging for patients with malignant pleural mesothelioma with the routine use of positron emission tomography (PET).

Methods: We performed a retrospective review of our prospectively maintained database from February 2014 to May 2019. Inclusion criteria were patients who had disease in the chest that was deemed potentially resectable by radiographic criteria and who underwent DL as part of the staging evaluation before surgery.

Results: Of 187 patients (71% men, 80% epithelial) who underwent DL during staging, 76% proceeded to surgery; 22% were unresectable at exploratory thoracotomy and 78% underwent resection (pleurectomy and decortication, 68%; extrapleural pneumonectomy, 32%). Also, 89% had a PET computed tomography (CT), and 11% had a preoperative CT without PET. DL revealed peritoneal disease in 17%. Among patients with pathologically proven disease at DL, 77% had negative PET-CT imaging. Based on the pathologic findings at DL the sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 23%, 78%, 17%, and 83%, respectively. The accuracy of PET-CT was 68%.

Conclusions: PET-CT has low sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. DL as part of the preoperative staging defines an important subset of patients with bicavitary disease. We recommend DL as a component of staging before surgery.

Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

In plain English

This retrospective review used a Baylor College of Medicine (Houston) database from February 2014 to May 2019. Of 365 patients with malignant pleural mesothelioma, 187 judged possible surgical candidates had diagnostic laparoscopy (a keyhole examination of the abdomen with biopsies, plus fluid washings if the lining looked normal) during staging; 142 went on to surgery. 166 also had PET scans, and 127 (67.9%) had recorded asbestos exposure. Laparoscopy found abdominal disease in 16.6%. Of those with proven abdominal disease, 77.4% had negative imaging. Checked against laparoscopy in all 187 patients, including those with CT but no PET, preoperative imaging had a sensitivity of 22.6% and accuracy of 68.4%; among the 166 with PET, results were almost identical (accuracy 68.7%). Random biopsies found disease in 5% of 140 patients without visible disease. Survival did not differ significantly by abdominal disease; the authors said their results were not powered to judge whether laparoscopy influences long-term survival. The authors concluded that PET-CT is insufficiently sensitive and accurate for peritoneal disease, and recommended laparoscopy in staging. They noted their patients were highly selected.

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 review of a prospectively maintained database at a single institution
• Who was studied: 187 of 365 patients with malignant pleural mesothelioma evaluated at Baylor College of Medicine, Houston, Texas, February 2014 to May 2019. These were patients considered potentially operative who underwent diagnostic laparoscopy during staging. 71% were men and 80% had epithelioid histology. 142 of the 187 went on to surgery.
• Exposure: Diagnostic laparoscopy with biopsy of visible implants. When the peritoneum appeared normal, it also included saline lavage for cytology and 4-quadrant biopsies. Findings were compared with preoperative CT and PET imaging. Asbestos exposure was recorded as a patient characteristic, but no fiber types or exposure doses were given.
• Main results:
  • All 187 patients had CT, and 166 had PET.
  • 142 of the 187 patients underwent surgery.
  • Diagnostic laparoscopy found disease in the abdomen in 16.6% of the 187 patients (31 patients).
  • In the comparison for all 187 patients, which included those with CT but no PET, the article reported a sensitivity of 22.6% and a positive predictive value of 16.7% against disease proven at laparoscopy. The article labels these as PET-CT results.
  • In the same all-187 comparison, the negative predictive value was 83.4% and the accuracy of imaging for predicting abdominal disease was 68.4%. The abstract gives specificity as 78%.
  • Excluding patients who had CT only, the results were almost identical to those for the entire cohort.
  • Among the 166 patients who had PET-CT, 16.9% had disease in the peritoneum.
  • In the PET analysis, the article reported PET-CT accuracy as 68.7%.
  • Among patients with proven peritoneal disease, 22.6% had suspicious findings on imaging and 77.4% had negative imaging.
  • Of visible peritoneal lesions biopsied during laparoscopy, 46.8% were positive on final pathology.
  • Among 140 patients without visible disease at laparoscopy, 5% had disease on random biopsies and 2 had disease by cytology.
  • Among patients who underwent cytoreductive surgery, median overall survival was 30 months with abdominal disease versus 21.2 months without it. Two-year overall survival was 58.3% versus 43.8%. The difference was not statistically significant (P = .25).
  • Asbestos exposure was recorded as present in 127 (67.9%) of the 187 patients.
• The authors' conclusion: The authors concluded that PET-CT has insufficient sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. They recommended diagnostic laparoscopy with lavage, biopsy of suspicious lesions, and random 4-quadrant biopsies as part of preoperative staging.
• Limitations the authors state:
  • The cohort was a highly selected group of patients referred to a quaternary care cancer center.
  • Imaging was not uniform, in an effort to limit patient expense.
  • Not all patients received diagnostic laparoscopy when the program first started.
  • The cohort was heterogeneous.
  • The results were not powered to conclude whether diagnostic laparoscopy influences long-term survival.

Topics

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

Medical terms in this study, explained in our Lexicon: Diagnostic Laparoscopy, Staging, Pleural Mesothelioma, Cytoreductive Surgery, Unresectable, Thoracotomy, Extrapleural Pneumonectomy (EPP), PET-CT.

Related studies

• Use of computed tomography and positron emission tomography/computed tomography for staging of local extent in patients with malignant pleural mesothelioma — T. Frauenfelder, P. Kestenholz, et al. (2015)
• 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography fused imaging in malignant mesothelioma patients: looking from outside is not enough — E. Roca, S. Laroumagne, et al. (2013)
• High performance of F-fluorodeoxyglucose positron emission tomography and contrast-enhanced CT in a rapid outpatient diagnostic program for patients with suspected lung cancer — P. Brocken, H.F. van der Heijden, et al. (2014)
• Positron Emission Tomography/Computed Tomography for the Pleural Staging of Malignant Pleural Mesothelioma: How Accurate Is It? — V. Pinelli, E. Roca, et al. (2015)
• The role of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiating between benign and malignant adrenal lesions — P. Ozcan Kara, T. Kara, et al. (2011)
• Positron emission tomography with f18-fluorodeoxyglucose in the staging and preoperative evaluation of malignant pleural mesothelioma — D.B. Schneider, C. Clary-Macy, et al. (2000)

Browse more research in The Annals of Thoracic Surgery, or return to medical research.