Role Of PET/CT In The Management Of Burkitt Lymphoma

Burkitt lymphoma (BL) is a highly aggressive and chemosensitive B cell non-Hodgkin lymphoma derived from germinal or post-germinal center B cells, which affects commonly extranodal sites. Although studies have described 100% of 18F-FDG avidity in BL, PET/CT is not routinely used in those patients being only recommended in the context of a clinical trial. The aim of the present study is to evaluate retrospectively, the role of PET/CT instead of CT scan alone both to stage newly diagnosed BL patients as well as to evaluate disease response after chemotherapy.

53 PET/CT (20 PET/CT at diagnosis, 28 after first line treatment and 5 to monitor residual disease detected in response assessment PET/CT) were performed in 32 patients, between 2006 y 2012. Locations of involved areas were registered comparing staging CT and PET/CT and were classified as discrepancy or not.

Patientxs baseline characteristics are summarized in table 1. At diagnosis, abdominal adenopathies had the highest SUVmax with a mean of 14,83 (3,5-35). Discrepancies were found in 64,7% of patients who had both imaging test available at diagnosis (n=17), almost all of them in extranodal sites. These findings upstaged 12% patients from localized to advanced disease. Sensitivity of PET/CT and CT was 100% and 53%, respectively. Regarding the response assessment, in 5 patients out of 13 (38%) who had both imaging test, the PET/CT after first-line treatment was negative whereas the CT demonstrated residual masses. No relapses were observed in those patients. Among 28 patients with a PET/CT available after first-line treatment, CR was attained in 22 patients; one true-positive and 5 false-positive lesions (FP) (1 nodal and 4 extranodal) were detected after completing treatment. SUVmax of FP single nodal site was 2,6 as compared to a mean of 14,9 for the positive lesions at diagnosis while the mean SUVmax of false-positive extranodal sites was 4,4 as compared to 12,1 at diagnosis. NPV was 100% and PPV 16%. SUVmax value of FP lesion was<60% of diagnosis in all cases. Thus, with a cut-off value SUVmax above 60% of that of diagnosis, the PPV is also 100%.

as compared to CT scan, a more accurate staging in BL can be obtained using PET/CT. Regarding response assessment, NPV reaches 100% and, using a cut-off value for the SUVmax of 60% below the value of diagnosis, also a 100% PPV is observed.

No relevant conflicts of interest to declare.