Page 45 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation

Predictive value of interim PET in DLBCL
Keywords
Aggressive non-Hodgkin’s lymphoma. Diffuse large B-cell lymphoma. Positron- emission tomography. Systematic review. Meta-analysis.
Introduction
Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of adult non-Hodgkin lymphoma (NHL) cases, and is associated with an aggressive clinical course. There are several potentially effective first-line chemotherapy regimens of which most consist of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). The addition of the monoclonal antibody rituximab (R) to this regimen (R-CHOP) has significantly improved the outcome of DLBCL patients [1,2]. However, treatment failure is still an important problem as the 3-year progression-free survival (PFS) of DLBCL patients is approximately 60– 70% [3].
Commonly used prognostic indices are the International Prognostic Index (IPI) [4,5], or the more powerful Revised-IPI (R-IPI) [6], and National Comprehensive Cancer Network IPI (NCCN-IPI) [7]. These indices can be used for risk-stratification to predict a poor outcome after R-CHOP. It is important to identify a poor outcome as soon as possible because these patients could benefit from a switch to a second-line treatment or high-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) as an upfront treatment [8]. 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) after a few cycles of therapy, also known as interim 18F-FDG PET, is of increasing interest, as it may facilitate early change of treatment and prevent unnecessary side effects [9]. In recent decades several visual criteria for interpretation of 18F-FDG PET have been developed, for example, the EORTC, PERCIST, and International Harmonization Project (IHP) criteria as well as the Deauville scoring system [9–13]. Nowadays the latter is widely adopted for interpretation of response evaluation with 18F-FDG PET in DLBCL [9,13].
Interim 18F-FDG PET has shown high predictive value in Hodgkin lymphoma [14]; however, according to previous reviews, the role of interim 18F-FDG PET in DLBCL is still unknown [15–18]. From these studies it can be concluded that
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