Catheter Tract Metastasis in Mesothelioma Patients with Indwelling Pleural Catheters: A Retrospective Cohort Study

Our plain-English summary of Catheter Tract Metastasis in Mesothelioma Patients with Indwelling Pleural Catheters: A Retrospective Cohort Study, by M.A. Mitchell, P. Li, C. Pease, et al (Respiration; International Review of Thoracic Diseases, 2019).

The study

• Authors: M.A. Mitchell, P. Li, C. Pease, S. Hosseini, C. Souza, T. Zhang, K. Amjadi
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2019;97(5):428-435
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Use of indwelling pleural catheters (IPCs) for the management of symptomatic pleural effusions in patients with mesothelioma has increased in popularity. An important concern with this approach is the potential for the development of catheter tract metastasis (CTM).

Objectives: To determine the incidence of IPC-related CTM in patients with malignant pleural mesothelioma (MPM).

Methods: In this single-center retrospective cohort study, patients with biopsy-confirmed MPM who had an IPC inserted between May 2006 and July 2017 were identified from a prospectively collected database. Thoracic CT scans following IPC insertion were reviewed to assess for evidence of CTM. Patients were followed until death or last documented patient encounter with a minimum of 6-month follow-up.

Results: A total of 90 patients were included in the cohort. CTM was identified in 23 of 90 patients (26%). Median time from IPC insertion to CTM was 408 days (interquartile range 196-721 days). Medical thoracoscopy at the time of IPC insertion did not lead to a significantly increased odds of CTM (OR 2.30; 95% CI 0.66-7.94; p = 0.19). Incidence of CTM was not different between mesothelioma subtypes (p = 0.09). Patient-reported dyspnea scores were improved following IPC insertion in 80% of patients.

Conclusions: CTM was identified in over a quarter of MPM patients when follow-up imaging was reviewed. Treating physicians should be cognizant of the possibility of CTM at the site of prior IPC.

© 2018 S. Karger AG, Basel.

In plain English

This retrospective cohort study at one center in Ottawa, Canada, looked at 90 adults with malignant pleural mesothelioma who had an indwelling pleural catheter (a chest drainage tube) inserted between May 2006 and July 2017. Asbestos exposure was not examined. The authors reviewed follow-up chest CT scans for catheter tract metastasis: tumor growing in the chest wall where the catheter was or had been. It was found in 23 of 90 patients (26%), a median of 408 days after insertion. In 19 of the 23 it appeared after catheter removal. Original radiology reports described this spread, or an uncertain nodule under the skin there, in only 9 of the 23. Patients died a median of 49 days after its identification. Medical thoracoscopy at insertion was not linked to significantly higher odds (adjusted odds ratio 2.30; 95% CI 0.66–7.94). Breathlessness scores improved in 62 of 78 patients (80%). The authors concluded that over a quarter of patients developed this spread and that physicians should be aware of it. They noted the small number of cases and lack of biopsy confirmation.

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: single-center retrospective cohort study using a prospectively collected clinic database and review of follow-up CT scans
• Who was studied: 90 adult patients with pathologically diagnosed malignant pleural mesothelioma (MPM) who had an indwelling pleural catheter (IPC) inserted for a malignant pleural effusion between May 2006 and July 2017. They were drawn from 1,850 patients in an academic, tertiary-care pleural disease clinic database in Ottawa, Canada. 78 (87%) were male, with a mean age at diagnosis of 74 years.
• Exposure: Insertion of an indwelling pleural catheter (PleurX). 58 patients (64%) also had medical thoracoscopy at the time of insertion. Asbestos exposure was not studied; it is mentioned only in the introduction as background.
• Main results:
  • Catheter tract metastasis (CTM) was identified in 23 of 90 patients (26%).
  • Median time from IPC insertion to identification of CTM was 408 days (IQR 196–721 days).
  • The initial radiology CT report described either CTM or an indeterminate subcutaneous nodule at the prior IPC site in only 9 of 23 (39%) patients with CTM.
  • 19 (83%) of the CTM cases occurred after the IPC had been removed.
  • Median time from identification of CTM to death was 49 days (IQR 16–107 days).
  • CTM occurred in 17 of 58 patients (29%) who had medical thoracoscopy at insertion and in 6 of 32 (18%) who did not. In the multivariate analysis this difference was not statistically significant (adjusted OR 2.30; 95% CI 0.66–7.94; p = 0.19).
  • The incidence of CTM did not differ significantly between mesothelioma subtypes (p = 0.09).
  • Patient-reported dyspnea (breathlessness) scores improved after IPC insertion in 62 of 78 patients (80%) (95% CI 68.6–87.8%). Data were missing for 12 patients.
  • IPC-related pleural infection occurred in 1 patient (1%).
• The authors' conclusion: The authors concluded that over a quarter of patients developed CTM when follow-up CT imaging was reviewed, that CTM is largely underreported, and that radiologists and treating physicians should be aware of the possibility of CTM at the site of a prior IPC.
• Limitations the authors state:
  • Retrospective design, and the total number of CTM cases was relatively small, so comparisons between groups may be underpowered.
  • CTM was diagnosed on imaging and was not biopsy-proven.
  • The study lacked data on patient-reported symptoms, so the authors could not confirm whether patients given radiotherapy to the CTM site had symptoms.
  • The benefit of CT screening for CTM could not be determined from these results.
  • The number of follow-up CT scans varied between patients, with some having minimal imaging. This may have caused detection bias and an underestimate of CTM.
  • The results cannot be applied to patients without MPM.

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: Tract Metastasis, Mesothelioma, Indwelling Pleural Catheter, Cohort Study, Pleural Effusion, Pleural Mesothelioma, Biopsy, CT Scan.

Related studies

• Catheter tract metastasis associated with indwelling pleural catheters — R. Thomas, C.A. Budgeon, et al. (2014)
• Pseudo-tumor mimicking indwelling pleural catheter tract metastasis in mesothelioma — R.L. Shrestha, B.A. Wood, et al. (2014)
• Protocol of the Australasian Malignant Pleural Effusion-2 (AMPLE-2) trial: a multicentre randomised study of aggressive versus symptom-guided drainage via indwelling pleural catheters — M. Azzopardi, R. Thomas, et al. (2016)
• Tract metastasis in patients with long-term pleural catheter-computed tomography diagnosis and longitudinal assessment — F. Hamad, C. Souza, et al. (2021)
• Intrapleural Fibrinolysis for the Treatment of Indwelling Pleural Catheter-Related Symptomatic Loculations: A Multicenter Observational Study — R. Thomas, F. Piccolo, et al. (2015)
• Aggressive versus symptom-guided drainage of malignant pleural effusion via indwelling pleural catheters (AMPLE-2): an open-label randomised trial — S. Muruganandan, M. Azzopardi, et al. (2018)

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