Prognosis estimation under the light of metabolic tumor parameters on initial FDG-PET/CT in patients with primary extranodal lymphoma
Objective: Non-Hodgkin’s lymphomas arising from the tissues other than primary lymphatic organs are called primary extranodal lymphoma. Most of the studies evaluated metabolic tumor parameters in different organs and histopathologic variants of this disease generally for treatment response. We aimed to evaluate the prognostic value of metabolic tumor parameters derived from initial FDG-PET/CT in patients with a medley of primary extranodal lymphoma in this study.
Material and Methods: There are 67 patients with primary extranodal lymphoma for whom FDG-PET/CT was requested for primary staging. Quantitative PET/CT parameters (SUVmax, SUVmean, MTV, TLG) were used to estimate disease-free survival and overall survival.
Results: SUVmean, MTV and TLG were found statistically significant after multivariate analysis. SUVmean remained significant after ROC curve analysis. Sensitivity and specificity were calculated as 88% and 64%, respectively when the cut-off value of SUVmean was chosen as 5.15. After the investigation of primary presentation sites and histopathological variants according to recurrence, there is no difference amongst the variants. But primary site of extranodal lymphomas is statistically important (p=0.014). Testis and central nerve system lymphomas has higher recurrence rate (62.5%, 73%, respectively).
Conclusion: High SUVmean, MTV and TLG values obtained from primary staging FDG-PET/CT are potential risk factors for both disease-free survival and overall survival in primary extranodal lymphoma. SUVmean is the most significant one amongst them for estimating recurrence/metastasis.