Diagnostic CT Scan for Mesothelioma: More is Better

A new report out of the UK suggests that a thorough diagnostic CT scan for pleural mesothelioma should include images of the abdomen and pelvis, as well as the chest. 

When a person goes to the doctor with early signs of malignant pleural mesothelioma, a CT scan of the chest is often the next step in making a diagnosis.

CT scans create a 3-dimensional image of internal organs, making it easier to spot mesothelioma tumors. 

But a research team led by the University of Bristol says a diagnostic CT scan that shows only the chest might miss mesothelioma tumors in other areas.

How a Diagnostic CT Scan Works

CT stands for computerized tomography. CT scanning is an advanced type of X-ray. Standard X-rays show only a 2-dimensional image. But a diagnostic CT scan takes multiple images of the same area. A computer compiles the images into a 3D model of the internal landscape. 

CT scanning is an important part of the diagnostic process for pleural mesothelioma. Pleural mesothelioma tumors do not grow in a ball like some other types of tumors. They grow across the membrane around the lungs and can be thin and irregularly-shaped. This can make them hard to spot on a standard X-ray.

A diagnostic CT scan offers better odds of detecting a mesothelioma tumor as early as possible.

Finding Unexpected Tumors

A collection of fluid on one side of the chest is a common sign of mesothelioma and a few other types of cancer. It is called one-sided or unilateral pleural effusion. When a patient comes in with unilateral pleural effusion, the doctor usually orders a diagnostic CT scan of the chest. 

But the UK study suggests this may not be enough. 

Their study looked at the cases of 249 patients with unilateral pleural effusion. The patients received a diagnostic CT scan that included their chest (thorax), abdomen, and pelvis.  

Fifty-six percent of patients turned out to have cancer or some other “clinically significant” issue in their chest. This was not unexpected. But a quarter of the patients scanned had a “clinically significant” finding below the diaphragm. 

The UK researchers say performing a diagnostic CT scan of the entire area is likely to catch problems that might otherwise go unnoticed. 

“Integrating this approach into standard practice allows more rapid identification of the primary malignancy, upstaging lesions or alternative sites for biopsy,” writes lead author Tom Syer in the BMJ publication Thorax. 

The UK has one of the highest per capita rates of mesothelioma in the world. Scientists believe this is because of the country’s high use of asbestos during post-World War II rebuilding efforts. 

Source:

Syer, T, et al, “Investigation of a unilateral pleural effusion: What CT scan coverage is optimal?”, March 26, 2020, Thorax, Epub ahead of print, https://thorax.bmj.com/content/early/2020/03/26/thoraxjnl-2019-214309