Diagnostic Utility of 18F-FDG PECT/CT in Assessment of Post-therapy Remission or Relapse of Lymphoma

Background: Treatment and prognosis of lymphoma depend on accurate staging and evaluation. Relapsed Lymphomas represent great problem in accurate quick diagnosis that imply appropriate treatment. Aim of the work: To evaluate diagnostic utility of 18F-FDG PECT/CT in assessment of treatment response and identification of disease relapse. Patients and Methods: This prospective study were conducted on 49 consecutive patients with histologically verified lymphoma. They were 27/49 (55.1%) male and 22/49 (44.9%) female aged 37.83±2.29. All patients were subjected to pretreatment as well a follow up clinical, laboratory, CT PET-CT. PET-CT findings were classified as positive and negative according to remission status and relapse. The sensitivity, specificity and accuracy of PET- CT in assessment of the remission status and relapse were calculated and to be confirmed by open or laparoscopic biopsy. Results: PET-CT detected complete regression in 28 patients (57.14%), partial regression in 4 patients (8.16%), stationary course in 2 patients (4.08%), progression / relapse in 15 patients (30.61%). According to PET/CT 9 (23%) patients were true positive, 25 (65%) were true negative and 5 (13%) were false negative with sensitivity, specificity, positive p predictive value and negative predictive value of 95% and 91%, 90% and 98%, respectively. Conclusion: Our results confirm FDG-PET as a valid tool for assessment of treatment response and detection of relapsing lymphoma. We recommended further multicentric prospective studies that incorporates a larger number of patients should be implemented to define the exact relation between certain clinical, pathological, laboratory and PET factors and fate of the disease.