Use of staging PET/CT better defines the extent of mantle cell lymphoma (MCL) in certain compartments, adding important information for treatment decisions, a cohort study suggests. However, patient selection and evaluation criteria are important for its utility.
Courtesy Wikimedia Commons/Nephron/Creative Commons
Intermediate magnification micrograph of mantle cell lymphoma of the terminal ileum.
“A correct and early identification of initial disease could be crucial because it could affect patient management and therapeutic choice,” Domenico Albano, MD, a nuclear medicine physician at the University of Brescia (Italy) and Spedali Civili Brescia, and colleagues wrote in Clinical Lymphoma, Myeloma, & Leukemia.
Using retrospective data from two centers and 122 patients with MCL, the investigators compared the utility of staging 18F-fluorodeoxyglucose (18F-FDG) PET/CT with that of other modalities used for detecting disease in specific compartments. They also assessed its impact on patient management.
The study results showed that, with the exception of a single patient having bone marrow involvement, all patients had positive PET/CT results, with detection of at least one hypermetabolic lesion.
For assessing nodal involvement, compared with CT alone, PET/CT detected additional lesions in 21% of patients. Splenic lesions were detected by PET/CT in 49% of patients and by CT alone in 47%.
For assessing bone marrow involvement, compared with bone marrow biopsy, PET/CT had a sensitivity of 52%, a specificity of 98%, a positive predictive value of 97%, a negative predictive value of 65%, and an overall accuracy of 74%.
For gastrointestinal involvement, compared with endoscopy, PET/CT had a sensitivity of 64% (78% after excluding diabetic patients taking metformin), a specificity of 91% (92%), a positive predictive value of 69% (72%), a negative predictive value of 90% (94%), and an overall accuracy of 85% (89%).
Ultimately, relative to CT alone, PET/CT altered stage and management in 19% of patients. Specifically, this imaging led to up-staging in 17% of patients, prompting clinicians to switch to more-aggressive chemotherapy, and down-staging in 2% of patients, prompting clinicians to skip unnecessary invasive therapies.
“We demonstrated that 18F-FDG pathologic uptake in MCL occurred in almost all patients, with excellent detection rate in nodal and splenic disease – indeed, better than CT,” the researchers wrote. “When we analyzed bone marrow and gastrointestinal involvement, the selection of patients excluding all conditions potentially affecting organ uptake and the use of specific criteria for the evaluation of these organs seemed to be crucial. Within these caveats, PET/CT showed good specificity for bone marrow and gastrointestinal evaluation.”
Study funding was not disclosed. Dr. Albano reported having no relevant conflicts of interest.
SOURCE: Albano D et al. Clin Lymphoma Myeloma Leuk. 2019 Aug;19(8):e457-64.