They say ‘a picture is worth a thousand words.’ In medical imaging—where images are used by doctors to guide therapies—two pictures may be even more valuable than one.
That is what a team of researchers at the Princess Margaret Cancer Centre found when they combined two types of medical imaging techniques, positron emission tomography (PET) and computed tomography (CT), to diagnose lymphoma patients.
While CT scans provide location and structural information about an individual’s tumour, PET is used to visualize cellular metabolism—a useful strategy for detecting fast growing cancerous cells. This complete snapshot of an individual’s tumor can help determine its location and severity (known as ‘staging’) prior to therapy, allowing clinicians to plan effective treatment.
“Despite recent guidelines that recommend PET/CT versus CT alone for more accurate staging of patients with lymphoma, the value of using PET imaging in addition to CT on clinical outcomes is not fully clear,” says Dr. Ur Metser, Division Head of Molecular Imaging at Princess Margaret Cancer Centre and Core Lead at the Techna Institute.
To address this knowledge gap, the research team compared the effect that PET/CT staging versus CT staging alone had on the management and outcomes of 850 individuals with lymphoma.
The added information provided by combined imaging with PET/CT changed the disease stage from “early” to “advanced” in about one in five of these patients. This changed treatment plans in around four out of ten participants. Importantly, for patients with aggressive non-Hodgkin’s lymphoma treated according to PET/CT data, there was improved survival at one-year compared to those treated according to CT alone.
“In this study, we were able to demonstrate the importance of accurate staging of lymphomas, which allows clinicians to effectively manage and plan treatment,” says Dr. Metser. “Adding PET imaging to a patient’s medical examination for certain types of lymphoma can significantly impact their survival.”
This work was supported by Ontario Ministry of Health and Long-Term Care (MOHLTC), Cancer Care Ontario and The Princess Margaret Cancer Foundation.
Metser U, Prica A, Hodgson D, Mozuraitis M, Eberg M, Mak V, Green B, Singnurkar A, Dudebout J, MacCrostie P, Tau N, Mittmann N, Langer DL. Effect of PET/CT on the management and outcomes of participants with Hodgkin and aggressive non-Hodgkin lymphoma. Radiology. 2018 Dec 4. doi: 10.1148/radiol.2018181519.
Dr. Ur Metser, Division Head of Molecular Imaging at Princess Margaret Cancer Centre and Core Lead at the Techna Institute.