Dynamic contrast-enhanced CT for the assessment of tumour response in malignant pleural mesothelioma: a pilot study

Our plain-English summary of Dynamic contrast-enhanced CT for the assessment of tumour response in malignant pleural mesothelioma: a pilot study, by E. Gudmundsson, Z. Labby, C.M. Straus, et al (European Radiology, 2019).

The study

• Authors: E. Gudmundsson, Z. Labby, C.M. Straus, W.F. Sensakovic, F. Li, B. Rose, A. Cunliffe, H.L. Kindler, S.G. Armato
• Journal: European Radiology
• Published: 2019;29(2):682-688
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: The aim of this pilot study was to investigate the utility of haemodynamic parameters derived from dynamic contrast-enhanced computed tomography (DCE-CT) scans in the assessment of tumour response to treatment in malignant pleural mesothelioma (MPM) patients.

Methods: The patient cohort included nine patients undergoing chemotherapy and five patients on observation. Each patient underwent two DCE-CT scans separated by approximately 2 months. The DCE-CT parameters of tissue blood flow (BF) and tissue blood volume (BV) were obtained within the dynamically imaged tumour. Mean relative changes in tumour DCE-CT parameters between scans were compared between the on-treatment and on-observation cohorts. DCE-CT parameter changes were correlated with relative change in tumour bulk evaluated according to the modified RECIST protocol.

Results: Differing trends in relative change in BF and BV between scans were found between the two patient groups (p = 0.19 and p = 0.06 for BF and BV, respectively). No significant rank correlations were found when comparing relative changes in DCE-CT parameters with relative change in tumour bulk.

Conclusions: Differing trends in the relative change of BF and BV between patients on treatment and on observation indicate the potential of DCE-CT for the assessment of pharmacodynamic endpoints with respect to treatment in MPM. A future study with a larger patient cohort and unified treatment regimens should be undertaken to confirm the results of this pilot study.

Key Points: • CT-derived haemodynamic parameters show differing trends between malignant pleural mesothelioma patients on treatment and patients off treatment • Changes in haemodynamic parameters do not correlate with changes in tumour bulk as measured according to the modified RECIST protocol • Differing trends across the two patient groups indicate the potential sensitivity of DCE-CT to assess pharmacodynamic endpoints in the treatment of MPM.

In plain English

This pilot study, done at the University of Chicago, tested whether a CT scan that tracks injected contrast dye over time (dynamic contrast-enhanced CT) could show how malignant pleural mesothelioma tumours respond to treatment. It did not study asbestos exposure. Fourteen patients enrolled between mid-2010 and late 2013. Nine were receiving chemotherapy, on several different regimens, and five were under observation without therapy. Each had two scans about two months apart that measured tumour blood flow and tumour blood volume. In the treatment group, median blood flow fell 16.1% and median blood volume fell 9.4%. In the observation group, median blood flow fell 1.9% and median blood volume rose 5.8%. These group differences were not statistically significant (p = 0.19 for blood flow, p = 0.06 for blood volume). Changes in blood flow or volume did not significantly correlate with changes in tumour thickness measured by modified RECIST. The authors concluded that the differing trends indicate the potential of this scan for assessing treatment effects, and that a larger study with uniform treatments is needed. They noted the small, mixed-treatment group 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: Prospective pilot imaging study at one institution comparing patients on treatment with patients on observation
• Who was studied: 14 patients with pathologically confirmed malignant pleural mesothelioma at the University of Chicago, accrued mid-2010 to late 2013: 9 on chemotherapeutic treatment, 5 on observation; 11 male, 3 female; median age at diagnosis 76
• Exposure: Asbestos exposure was not studied. The comparison was between patients receiving various chemotherapy or targeted-drug regimens and patients receiving no therapy, each scanned twice with dynamic contrast-enhanced CT about 2 months apart
• Main results:
  • Tumour blood flow: median change of -16.1% (range -22.2% to 8.4%) in the treatment group versus -1.9% (range -6.7% to 0.1%) in the observation group; p = 0.19; estimated median difference -11.7% (95% CI -19.6% to 4.3%)
  • Tumour blood volume: median change of -9.4% (range -18.6% to 11.4%) in the treatment group versus 5.8% (range -1.5% to 14.5%) in the observation group; p = 0.06; estimated median difference -14.5% (95% CI -23.3% to 3.5%)
  • The differences between the two groups in blood flow and blood volume change were not statistically significant (the significance level was set at 0.0063 after correction for 8 tests)
  • In all patients, changes in blood flow or blood volume did not significantly correlate with change in tumour thickness by modified RECIST (blood flow rho -0.165, p = 0.57; blood volume rho -0.437, p = 0.12)
  • The tumour analysed with dynamic imaging was a median of 9% (range 4–75%) of each patient's total tumour volume in the chest
• The authors' conclusion: The authors concluded that the differing trends in blood flow and blood volume between treated and observed patients indicate the potential of dynamic contrast-enhanced CT for assessing treatment effects in malignant pleural mesothelioma. They said a larger study with unified treatment regimens is needed to confirm the results.
• Limitations the authors state:
  • The patient group was small, and the treatment group received a mix of different regimens
  • Links between blood-flow changes and patient survival were not examined, because treatments were not uniform and treatments outside the roughly 2-month window could not be controlled
  • The second dynamic imaging phase could not be used because its start time varied between scans

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, Chemotherapy, CT Scan, Modified RECIST (mRECIST).

Related studies

• 18F-Fluorodeoxyglucose PET/CT and dynamic contrast-enhanced MRI as imaging biomarkers in malignant pleural mesothelioma — D.O. Hall, C.E. Hooper, et al. (2018)
• Dual-input tracer kinetic modeling of dynamic contrast-enhanced MRI in thoracic malignancies — S.H. Lee, A. Rimner, et al. (2019)
• Characterization of mesothelioma and tissues present in contrast-enhanced thoracic CT scans — N. Corson, W.F. Sensakovic, et al. (2011)
• Revised Modified Response Evaluation Criteria in Solid Tumors for Assessment of Response in Malignant Pleural Mesothelioma (Version 1.1) — S.G. Armato, A.K. Nowak (2018)
• Variability of tumor area measurements for response assessment in malignant pleural mesothelioma — Z.E. Labby, C. Straus, et al. (2013)
• Optimization of response classification criteria for patients with malignant pleural mesothelioma — Z.E. Labby, S.G. Armato, et al. (2012)

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