Malignant mesothelioma patients could benefit from receiving a combination of two different imaging scans, PET and CT scans, to assess their response to treatment, according to two studies published in the journal Annals of Oncology.

In one study, 27 pleural mesothelioma patients undergoing first-line immunotherapy with ipilimumab and nivolumab (Opdivo® and Yervoy®, respectively) received baseline PET-CT scans at their initial diagnosis and additional scans every 12 weeks.

The addition of PET scans revealed a cell-level response to treatment in some patients that wouldn’t have been detected in a CT scan. The PET-CT scans showed that 8 patients responded to treatment, 7 showed disease stabilization, and 4 experienced disease progression.

This analysis indicates that the combination of these two imaging scans better identified which patients responded well to immunotherapy and could help keep future patients from ending their mesothelioma treatment prematurely.

What’s the Difference Between a PET Scan and CT Scan?

A computed tomography, or CT, scan operates as a digital X-ray imaging procedure that takes cross-sectional images or “slices” of the organs and tissues inside a patient. These scans can then be digitally stacked together to show a 3D image that doctors can review for any tumors or abnormalities.

A positron emission tomography, or PET, scan is a type of imaging technique that uses a small amount of radioactive substances to see the metabolic activity of the tissue cells in the body.

During the procedure, a technician administers radioactive sugar intravenously, which is absorbed by certain cells. As a result, these cells emit gamma rays that are picked up in the imaging scan. This provides information about the areas of the body affected by cancer and if they are responding to treatment.

While a CT scan informs doctors what the affected area looks like, a PET scan reveals what is happening within cancer cells. Combining these scans provides a more comprehensive picture of how a patient’s pleural mesothelioma is progressing and responding to treatment.

PET-CT Scans as a Prognostic Tool

A second Norwegian study followed 88 patients and emphasized the value of PET scans for a more accurate prognosis. PET-CT scans enabled researchers to divide patients into two subgroups based on low or high metabolic tumor volume (MTV).

Those with low MTV experienced better median overall survival and median progression-free survival. This signaled to researchers that PET scans could help provide patients with a better understanding of their projected life expectancy.

While the current use of PET-CT scans for pleural mesothelioma is limited, scientists continue to study whether incorporating both imaging tests may be a better way to determine patient prognosis and the length and efficacy of treatment.

Get Help Finding a Mesothelioma Specialist

Mesothelioma is an aggressive cancer that can make those fighting it feel defeated. However, studies like these offer hope to patients seeking more effective treatments that can help them live longer.

If you or someone you love has been diagnosed with mesothelioma, our Patient Advocates can help you find top specialists who provide the most innovative treatments available.

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beth swantekWritten by:

Contributing Author at Mesothelioma Hope

Beth Swantek has been writing about the dangers of asbestos since 2013. Beth served as a media professional for over 30 years and began her career as a broadcast journalist. After her daughter suffered a traumatic brain injury at birth, Beth has devoted her life to helping men and women experiencing deep loss — such as those living with mesothelioma.

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  1. Christoph, D.C.C., (2023). 2196P PET-CT detects response to treatment with ipilimumab and nivolumab in malignant mesothelioma far better than CT. Retrieved November 8, 2023, from
  2. John Hopkins Medicine. (2023). Positron Emission Tomography (PET). Retrieved November 8, 2023, from
  3. National Institutes of Health. (2023). Computed Tomography (CT). Retrieved from November 8, 2023, from
  4. Thunold, S.M.H., (2023). 2197P Prognostic value of 18F-FDG PET for patients with malignant pleural mesothelioma treated with double immunotherapy. Retrieved November 8, 2023, from

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