Detection of circulating tumour cells in peripheral blood of patients with malignant pleural mesothelioma

Our plain-English summary of Detection of circulating tumour cells in peripheral blood of patients with malignant pleural mesothelioma, by J. Raphael, C. Massard, I.Y. Gong, et al (Cancer Biomarkers, 2015).

The study

• Authors: J. Raphael, C. Massard, I.Y. Gong, F. Farace, J. Margery, F. Billiot, A. Hollebecque, B. Besse, J.C. Soria, D. Planchard
• Journal: Cancer Biomarkers
• Published: 2015;15(2):151-6
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The independent prognostic value of Circulating Tumour Cells (CTC) level has been demonstrated in several solid tumours. There is currently few data on Malignant Pleural Mesothelioma (MPM) and CTC. We investigated whether the presence of CTC was correlated with prognosis factors and treatment efficacy.

Methods/objectives: MPM patients (pts) were enrolled in a prospective monocentric study. CTC detection was made using the "CellSearch" assay. The correlation between the presence of CTC and worse prognosis factors was assessed using the X(2) test. Comparison of Overall Survival (OS) and Progression Free Survival (PFS) according to CTC detection was performed using the log-rank test.

Results: Twenty-seven MPM pts with a median follow-up of 4.2 months were included. CTC were detected in 44% of pts with a median level of 1.5. No significant correlation was observed between the presence of CTC and worse prognosis factors. Moreover, CTC detection was not a significant predictor of OS or PFS (p=0.155 and p=0.32 respectively).

Conclusions: CTC were detected in a small cohort of MPM patients. We couldn't demonstrate a significant prognostic value or a difference in OS/PFS between CTC levels. Further analyses, validation studies and detection techniques are needed to establish their real clinical value in MPM.

In plain English

This was a small prospective study at one French cancer centre, Gustave Roussy, of 27 consecutive patients with malignant pleural mesothelioma not treatable with curative surgery. Most (89%) had already received at least one line of treatment, and 15 of the 27 had a history of asbestos exposure. The researchers used a blood test called CellSearch to look for circulating tumour cells, cancer cells shed into the bloodstream. These cells were found in 12 patients (44%), with a median of 1.5 cells per 7.5 ml of blood. Their presence was not significantly linked to known signs of worse outlook such as sex, tumour type, stage or performance status. It also did not significantly predict overall survival from diagnosis (p = 0.155) or progression-free survival from the blood test, which counted progression or death (p = 0.32). The authors concluded that these cells can be detected in mesothelioma patients but could not be linked to worse prognosis or survival so far. They noted the small, heavily pretreated group, short follow-up (median 4.2 months), and that the test relies on a marker mesothelioma cells may not carry.

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: Prospective single-centre study of a blood biomarker (circulating tumour cells) in mesothelioma patients
• Who was studied: 27 consecutive patients with histologically confirmed malignant pleural mesothelioma not amenable to curative surgery, at one academic cancer centre (Gustave Roussy, Villejuif, France), enrolled 2011 to 2012. Most (89%) had already received at least one line of treatment; 3 (11%) had received no chemotherapy.
• Exposure: The study measured circulating tumour cells in blood, not asbestos exposure. Asbestos exposure was recorded only as a baseline characteristic: 15 patients (56%) exposed and 12 (44%) not exposed. It was not analysed further.
• Main results:
  • Circulating tumour cells were detected in 12 of the 27 patients (44%). 8 patients (29%) had fewer than 3 cells per 7.5 ml and 4 patients (15%) had 3 or more.
  • The median level of circulating tumour cells detected was 1.5 per 7.5 ml (range 1 to 36).
  • Detection of circulating tumour cells was not significantly associated with any of the worse-prognosis factors studied: male sex, histology, stage, performance status, and anemia, leucocytosis or thrombocytosis.
  • Overall survival, measured from diagnosis: patients with no circulating tumour cells had a median survival of 37 months (95% CI 26.74 to 47.26). Median survival was not reached in patients with at least 1 cell detected. The difference was not statistically significant (p = 0.155).
  • Progression-free survival measured from the blood test (PFS2), with either progression or death counted as an event, was 9.6 weeks (95% CI 1.1 to 18) in patients with no cells detected and 12 weeks (95% CI 6.4 to 17.6) in patients with at least 1 cell per 7.5 ml. The difference was not statistically significant (p = 0.32).
  • PFS2 was defined as the time from the circulating tumour cell measurement until progression or death.
  • Median follow-up was 4.2 months. At the time of analysis, 6 patients (22%) had died.
• The authors' conclusion: The authors concluded that circulating tumour cells can be detected in mesothelioma patients, but that so far their presence could not be correlated with worse prognosis or survival.
• Limitations the authors state:
  • The cohort was small and follow-up was short, which the authors said makes the survival analysis hard to interpret.
  • The patients were a highly selected, heterogeneous group. Most were pretreated, and only 11% had received no chemotherapy and were enrolled at diagnosis.
  • The survival results did not reflect typical survival in pleural mesothelioma, and the authors cautioned against generalizing them.
  • The CellSearch test captures cells using an epithelial marker (EpCAM) that mesothelioma cells may not express, especially in non-epithelioid disease. The authors called this a major limitation.

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: Pleural Mesothelioma, Prognosis, Overall Survival.

Related studies

• Circulating endothelial cell (CEC) as a diagnostic and prognostic marker in malignant pleural mesothelioma (MPM) — K. Yoneda, F. Tanaka, et al. (2012)
• Detection of circulating tumor cells with a novel microfluidic system in malignant pleural mesothelioma — K. Yoneda, T. Kuwata, et al. (2019)
• A liquid biopsy for detecting circulating mesothelial precursor cells: A new biomarker for diagnosis and prognosis in mesothelioma — B.T.V. Duong, L. Wu, et al. (2020)
• Circulating tumor cells (CTCs) in malignant pleural mesothelioma (MPM) — K. Yoneda, F. Tanaka, et al. (2014)
• EpCAM-independent capture of circulating tumor cells with a 'universal CTC-chip' — Y. Chikaishi, K. Yoneda, et al. (2017)
• Improved diagnosis and prognostication of patients with pleural malignant mesothelioma using biomarkers in pleural effusions and peripheral blood samples - a short report — N. Beije, J. Kraan, et al. (2017)

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