Malignant Local Seeding in Procedure Tracts of Pleural Mesothelioma: Incidence and Novel Risk Factors in 308 Patients

Our plain-English summary of Malignant Local Seeding in Procedure Tracts of Pleural Mesothelioma: Incidence and Novel Risk Factors in 308 Patients, by M. Lapidot, E. Mazzola, R. Bueno (Cancers, 2025).

The study

• Authors: M. Lapidot, E. Mazzola, R. Bueno
• Journal: Cancers
• Published: 2025;17(17)
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background/Objectives: Unlike other thoracic malignancies, seeding malignant cells along surgical tracts is a known complication of invasive diagnostic or therapeutic procedures for pleural mesothelioma (PM). We report the tract dissemination rate and risk factors in 308 consecutive patients treated over 9 years in a single institution who underwent pleurectomy decortication (PD). Methods: Clinical and outcome data were reviewed. Fisher's exact test, Kaplan-Meier estimators, and log-rank tests were used to identify significant risk factors for surgical tract dissemination and to compare overall survival. Results: There were 233 males (75.6%), 187 right-sided operations (61%), 190 (61.7%) epithelioid histology cases, and the median age was 69 (29-84). During the study, malignant cell dissemination in resected surgical tracts was diagnosed in 69 (22.4%) patients. The dissemination rates in epithelioid, biphasic, and sarcomatoid tumors were 24.7%, 20.4%, and 0%, respectively. Disseminated malignant surgical tract was associated with advanced nodal status (p = 0.001), advanced staging by the American Joint Committee on Cancer (AJCC 8th edition, p = 0.03), female sex (0.02), side of surgery (p = 0.03), and the number of video-assisted thoracoscopic surgery (VATS) ports (p = 0.003). In epithelioid mesothelioma, the median survival from diagnosis was 19.7 months in patients with tract seeding versus 36.3 months in patients without seeding (hazard ratio, 1.9; p = 0.001). Conclusions: Procedure tract dissemination occurs in almost every fourth patient with pleural mesothelioma and is associated with shorter overall survival in the epithelioid subtype.

In plain English

This study looked back at records from a single high-volume center. It covered 308 patients with pleural mesothelioma who had an operation called pleurectomy decortication between January 2010 and January 2019. During that operation, the sites of their earlier diagnostic procedures were removed and examined under the microscope. The article does not discuss asbestos. Mesothelioma cells were found in these procedure tracts in 69 patients (22.4%). The rates were 24.7% of epithelioid, 20.4% of biphasic and 0% of sarcomatoid tumors, a difference that was not statistically significant. Tract spread was more common in women than men (32.0% vs 19.3%), after left-sided surgery, with more advanced lymph node involvement and stage, and after keyhole (VATS) procedures with two or more ports rather than one (28.3% vs 14.1%). Among the 190 patients with epithelioid tumors, median survival from diagnosis was 19.7 months with tract spread versus 36.3 months without (hazard ratio 1.9). The authors concluded that tract spread was associated with shorter survival in epithelioid disease. They cautioned that the sex difference rested on few women and may be exaggerated.

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 from a single high-volume center
• Who was studied: 308 patients with pleural mesothelioma who underwent pleurectomy decortication with resection of prior diagnostic sites, January 2010 to January 2019, at a single center (author affiliations: Brigham and Women's Hospital, Boston); 233 men (75.6%), median age 69
• Exposure: Prior invasive diagnostic procedures whose tracts were resected: 282 VATS (keyhole) incisions and 24 thoracotomy incisions; 40 patients also had permanent indwelling drains. Asbestos exposure is not studied or discussed.
• Main results:
  • Malignant seeding of procedure tracts was found in 69 of 308 patients (22.4%)
  • Seeding rates were 24.7% in epithelioid, 20.4% in biphasic and 0% in sarcomatoid cases; the difference between histologies was not significant
  • Women had a higher seeding rate than men: 32.0% vs 19.3%, p = 0.02
  • Seeding was associated with advanced lymph node status (p = 0.001) and higher pathological stage (p = 0.03, AJCC 8th edition)
  • Left-sided operations had a higher seeding rate than right-sided ones: 35 (28.9%) vs 34 (18.2%), p = 0.03
  • Uniportal VATS had a lower seeding rate (14.1%) than VATS with two or more ports (28.3%), p = 0.003
  • Neither neoadjuvant chemotherapy nor T status was significantly associated with seeding
  • Of 40 patients with permanent indwelling drains, seeding of the drain tract was confirmed in 6 (15%)
  • Among 190 patients with epithelioid mesothelioma, median survival from diagnosis was 36.3 months without seeding vs 19.7 months with seeding (hazard ratio 1.9, p = 0.001)
  • In the epithelioid group, median survival from the time of surgery was 16.7 months with seeding vs 32.1 months without
  • No survival difference by seeding status was found in the entire cohort of 308 patients
• The authors' conclusion: The authors concluded that tract dissemination occurred in roughly a quarter of patients and was associated with shorter overall survival in epithelioid pleural mesothelioma. They recommended a single-port diagnostic approach, with the port placed so it can be removed during later surgery.
• Limitations the authors state:
  • Only 24 women had tract seeding, so the apparent difference between the sexes may be exaggerated and needs validation in larger multi-institutional cohorts

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Overall Survival, Epithelioid, Histology, Biphasic Mesothelioma, Sarcomatoid, Staging, AJCC.

Related studies

• Protocol for the surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial): an RCT evaluating whether prophylactic radiotherapy reduces the incidence of procedure tract metastases — A.O. Clive, P. Wilson, et al. (2015)
• Blue-collar work is a risk factor for developing IgG4-related disease of the biliary tract and pancreas — L.M. Hubers, A.R. Schuurman, et al. (2021)
• Prolonged survival and novel prognostic factors in women with pleural mesothelioma treated with extended pleurectomy decortication — M. Lapidot, E. Mazzola, et al. (2024)
• A randomised trial of single-dose radiotherapy to prevent procedure tract metastasis by malignant mesothelioma — S. Bydder, M. Phillips, et al. (2004)
• Prophylactic radiotherapy for the prevention of procedure-tract metastases after surgical and large-bore pleural procedures in malignant pleural mesothelioma (SMART): a multicentre, open-label, phase 3, randomised controlled trial — A.O. Clive, H. Taylor, et al. (2016)
• Prophylactic radiotherapy to prevent procedure-tract metastases — G. Zalcman, S. Brosseau, et al. (2016)

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