Positron Emission Tomographic Scans in Lymphoma: Convention and Controversy

Abstract

The use of sensitive and specific imaging techniques for accurate initial staging and evaluation of response to therapy in patients with lymphoma is essential for their optimal management. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) integrated with computed tomography (CT) has emerged as a powerful imaging tool and is being routinely used in staging, response evaluation, and posttreatment surveillance in patients with non-Hodgkin lymphoma and Hodgkin lymphoma. PET/CT is currently widely used in clinical practice, but the established clinical benefit is currently restricted to the posttreatment evaluation of Hodgkin lymphoma, diffuse large B-cell lymphoma, and follicular lymphoma. Although used in other histologic subtypes and in other clinical situations including response assessment, its impact on patient outcome remains to be demonstrated. We performed a literature search of PubMed from 1999 to 2011 using the following keywords: PET scan, FDG-PET, PET/CT, lymphoma. This review addresses the challenges and controversies in the use of PET/CT scans in the management of patients with lymphoma. I n most patients with lymphoma, positron emission tomographic (PET) scans show abnormalities at diagnosis. Normal findings on the scan after therapy is highly predictive of a good prognosis, particularly in patients with diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, and Hodgkin lymphoma. However, the optimal application of PET scans to the management of all patients with lymphoma remains problematic. The major controversies include the optimal timing of PET scans (for staging, during therapy, after completion of therapy, surveillance in remission), standardization of PET scan interpretation (visual interpretation compared with standard uptake value [SUV] calculation), what constitutes a positive PET scan result, and whether PET scans should be used to direct management (eg, does changing therapy in patients with positive findings on PET change outcome, should biopsies of sites with positive PET results be done routinely before a management change). Although a large body of literature addressing these topics exists, the studies are often difficult to compare, making definitive conclusions on all these issues difficult. The previously published studies often used different designs and variable reporting, making interpretation and comparison of the results difficult. In the early studies particularly, heterogeneous populations with different stages of disease and different histologic subtypes were included, making the clinical applicability of the studies' results difficult. More recent studies focusing on efforts to standardize the conduct and interpretation of PET scans and on riskadapted therapies based on interim PET scan results will, it is hoped, improve the management and outcome of patients with lymphoma. A literature search of PubMed from 1999 to 2011 was performed using the following keywords: PET scan, FDG-PET, PET/CT, lymphoma. We highlight the current standard use ...

Baseline and ongoing PET-derived factors predict detrimental effect or potential utility of 18F-FDG PET/CT (FDG-PET/CT) performed for surveillance in asymptomatic lymphoma patients in first remission

“…Another relevant issue related to the use of FDG-PET for relapse screening is the high prevalence of FP [26,27]. Besides affecting cost-effectiveness of PETsv, these findings are a source of anxiety and potentially further radiation exposure.…”

Use of positron emission tomography-computed tomography in the management of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

“…[2] However, FDG uptake is usually not appreciably increased in the malignant lymphocytes of some indolent lymphoid malignancies, including chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL). [3] In these diseases the value of the routine use of PET scans has not been established.…”

Relevance of Positron-Emission Therapy for Optimization of Treatment of Advanced Hodgkin’s Lymphoma Using Intensive ЕАСОРР-14 Program

“…У этих 6 пациентов рецидивы не возникли при сроке наблюдения 1-5 лет (p = 0,003). Эти результаты подтверждают данные литературы о высокой прогностической значимости отрицательных результатов ПЭТ после окончания ле-чения у больных ЛХ (95-100 % по данным литературы) и значительно меньшей значимости положительных результатов ПЭТ на этом этапе за счет большой частоты ложноположительных результатов [29][30][31][32][33].…”