When it comes to evaluating treatment response in mesothelioma, functional imaging techniques may do a better job than standard imaging.
That is the word from a team of UK researchers who compared different types of imaging techniques in the evaluation of pleural mesothelioma patients for an article in the journal Lung Cancer.
Imaging Techniques for Mesothelioma Tumors
Functional imaging, which includes techniques like positron emission tomography (PET), dynamic contrast-enhanced MRI, and diffusion-weighted MRI, are designed to tell doctors more than just the size or shape of the mesothelioma tumor. By using certain kinds of injectable tracers, these imaging studies reveal important information about cellular processes like metabolism, which is typically higher in mesothelioma cells than it is in normal cells.
“By quantifying how these measurements change with [mesothelioma] treatment, it is possible to observe treatment effects,” says Lin Cheng of the UK’s Institute of Cancer Research.
Mesothelioma Treatment Evaluation Impacted by Tumor Shape
One of the difficulties with tracking mesothelioma treatment response with standard imaging techniques is that mesothelioma tumors are often shaped differently than other types of solid tumors.
Mesothelioma tumors typically spread out in a thin sheet on the pleural membrane that surrounds the lungs, rather than in a ball like other cancers. For this reason, the RECIST criteria (Response Evaluation Criteria in Solid Tumours) used to evaluate more spherical tumors has to be modified to apply to mesothelioma.
The Importance of Measuring Mesothelioma Treatment Response
Mesothelioma treatment plans are highly individual and are developed based on information about the size and extent of the patient’s cancer as well as the patient’s age, history, and overall health.
It is vital for doctors treating mesothelioma to have an efficient and effective way to measure a patient’s response to treatment so they can easily change course if a given treatment is not working well.
New Methods for Evaluating Mesothelioma Tumors During Treatment
18 FDG-PET imaging is an up-and-coming tool for the assessment of treatment response in patients with mesothelioma. Studies have found that a decrease in the amount of tracer absorbed by mesothelioma cells is associated with positive response to treatment and with longer progression free mesothelioma survival.
Diffusion-weighted MRI (DWI) measures the movement of water molecules in mesothelioma tumors. The research team calls it a “promising functional MRI technique” for evaluating mesothelioma treatment.
Learn more about diagnostic imaging techniques for mesothelioma.
Cheng, L et al, “Response evaluation in mesothelioma: Beyond RECIST”, August 22, 2015, Lung Cancer, Epub ahead of print