The Value of Positron Emission Tomography Scan in Staging of Lymphoma in a Sample of Iraqi Patients

Abstract Background: A diverse range of illnesses known as lymphomas are caused by immune system constituent cells or their progenitors. 18 F-Fluorodeoxyglucose positron emission tomography (PET)/computerized tomography has been routine practice to improve the characterization and prognosis of both Hodgkin and non-Hodgkin lymphomas (NHLs). Objectives: The objective of the study was to assess the role of positron emission tomography (PET) scan in clinical evaluation of lymphoma and its ability to identify the correct stage of lymphoma. Patients and Methods: cross-sectional follow-up study was conducted on 50 patients with pathologically proven lymphoma in 2021 who were admitted to the hospital. All patients included in the study performed computed tomography (CT) and PET scan for initial staging. Results: In NHL, PET scan staging differed significantly from clinical in two stages; there were 7 patients versus none with Stage II according to clinical and PET scan staging, respectively. Furthermore, only five patients had Stage IV according to clinical staging versus 17 patients in PET scan staging. Accordingly, there was no agreement between the two modalities (κ = 0.085, 95% = 0.045–0.123, P = 0.394). In Hodgkin lymphoma (HL), the two modalities differ significantly in the appraisal of Stage IV, in which there were 2 patients based on clinical staging and 11 patients according to PET scan staging. Thus, there was a poor agreement between the two modalities (κ = 0.314, 95% confidence interval = 0.283–0.376, P = 0.002). PET scan upstaged 50% and 61.54% of the patients with HL and NHL, respectively, with a highly significant difference, whereas there was no change in staging for 50% and 34.62%, respectively, with a highly significant difference. In NHL, PET scan demonstrated higher positive bone marrow (BM) involvement than biopsy (34.62% vs. 19.23%) with a highly significant difference. Similarly, in HL, PET scan revealed far more positive BM involvement than biopsy (45.83% vs. 8.33%) with a highly significant difference. Conclusions: There is poor or no agreement between PET scan and clinical staging of lymphoma, with high detection with PET scan for BM involvement compared with CT scan, which leads to the identification of additional involved sites of patients with lymphoma.