CT and PET / CT with 18-FDG to evaluate the response to treatment in Hodgkin and non-Hodgkin lymphoma

Introduction: The assessment of lymphoma response to treatment is based on imaging studies. Objective: To correlate the assessment of lymphoma treatment response by computed tomography (CT) and by positron emission tomography/computed tomography (PET/CT). Method: Cross-sectional, observational study, where records of patients with lymphoma under surveillance by CT and PET/CT were reviewed. Results: The study population consisted of 43 patients with a mean age of 32.7 +/- 22.4 years; 26 (60.5 %) had a diagnosis of Hodgkin's lymphoma and 17 (9.5 %) had non-Hodgkin lymphoma. By CT, 34 (79.1 %) were diagnosed with disease and nine (20.9 %) without disease. The criteria used to assess the response was radiologist experience in 39 (90.7 %) and RECIST 1.1 criteria in four (9.3 %). The diagnosis by 18-FDG PET/CT was no response to treatment or partial response-recurrence in 32 (74.4 %) and response to treatment in 11 (25.6 %); with PERCIST criteria in 13 (30.2 %) and Deuaville criteria in 30 (69.8 %). When the diagnosis by CT versus 18-FDG PET/CT was compared, out of 11 patients with complete response on PET/CT, three had a similar CT diagnosis. Of the 34 patients with data consistent disease diagnosed by CT, 26 had similar results by 18-FDG PET/CT (p = 0.54). Conclusion: The value of lymphoma treatment response on CT does not agree with that obtained by 18-FDG PET/CT.