The value of 18F‐fluorodeoxyglucose positron emission tomography/computed tomography for staging of primary extranodal head and neck lymphomas

Abstract

Using a retrospective approach, the aim of this study was to confirm the previously described value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) in patients with primary extranodal lymphoma of the head and neck region. Additionally, the clinical significance of the semiquantitative analysis of the standardized uptake value (SUV), its predictive role in the follow-up setting, and its value in detection of synchronous primaries were studied. Retrospective chart review. Twenty-six patients with a primary extranodal head and neck lymphoma (22 diffuse large B-cell lymphoma, one Hodgkin's lymphoma, three malignant T-cell lymphomas) were included. We retrospectively evaluated the clinical outcomes according to the maximum standardized uptake values of the primary lesion (SUV(max)) and whether a positron emission tomography/computed tomography (PET/CT) was performed or not in the follow-up studies. The median SUV(max) was chosen as the cutoff value. The patients were then grouped as those with either low or high SUV(max), respective to the cutoff value. Event-free survival and cumulative survival were endpoints of interest. Nineteen patients (73%) were above the age of 60 years; the median age was 70 years (range, 28-87 years). Most primary sites were in the Waldeyer's ring (15 patients, 60%), whereas in four patients (27%) only the palatine tonsil was affected. The SUV(max) ranged from 5.8 to 33.9. In one patient, relevant fluorodeoxyglucose (FDG) uptake within the intestine revealed a cecal adenocarcinoma as a secondary primary. Twenty of the 25 clinically followed patients (80%) achieved complete remission after treatment. Patients with high SUV(max) showed favorable survival (log-rank test, P = .044). A tendency for longer survival within the group with follow-up PET/CT studies could be noted but with no significant statistical difference (P = .349). (18)F-FDG-PET/CT imaging is a potent primary staging tool. It also has application as an instrument for evaluation of follow-up and response to therapy in patients suffering from primary extranodal lymphoma and for detection of secondary malignancies. Furthermore, (18)F-FDG uptake by the primary lesion may be related to better survival.