Is There a Role for [18F]FDG PET-CT in Staging MALT Lymphoma?

Mikhail Kesler,Dan Cohen,Efrat Luttwak,Shir Hazut-Krauthammer,Einat Even-Sapir,Chava Perry,Irit Avivi,Yair Herishanu

doi:10.3390/cancers14030750

Abstract

Simple SummaryMALT lymphoma represents a relatively rare lymphoma subtype that arises in different extranodal anatomic locations. In the current paper we summarize our experience in assessing disease extent and metabolic characteristics of MALT lymphomas with [18F]FDG PET-CT at staging, and aim to highlight the strengths and challenges this imaging modality poses. In our data, all extranodal lesions located in subcutaneous-tissue, lung and liver were detected on PET, while some of those located in other tissues (such as along the digestive tract) were not detected on PET. We also evaluated the predictive role of PET in these patients, and found that increased [18F]FDG-uptake in extranodal lesions was associated with worse disease progression.The role of 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography—computed tomography (PET-CT) in assessing mucosa-associated lymphoid tissue (MALT) lymphoma is debatable. We retrospectively explored the role of [18F]FDG PET-CT in staging and predicting progression-free-survival (PFS) of patients with newly-diagnosed MALT lymphoma. Sixty-six studies were included. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were documented in the “hottest” extranodal and nodal lesions. Extranodal lesions and accompanying nodal disease were detected on PET in 38/66 (57.6%) and 13/66 (19.7%) studies, respectively. Detection rate of extranodal lesions differed significantly between those located in tissues with high/heterogeneous (e.g., stomach) vs low/homogenous (e.g., subcutaneous-tissue, lung) physiologic [18F]FDG-uptake (40.4% vs. 100%, p < 0.01). Nodal lesions had significantly lower SUVmax, MTV and TLG compared with extrandodal lesions in the same patients. Detection and [18F]FDG-avidity of extranodal lesions were higher in patients with advanced, bulky disease and concomitant marrow/nodal involvement. Increased SUVmax of extranodal lesions predicted shorter PFS (HR 1.10, 95% CI 1.01–1.19, p = 0.02). Higher SUVmax and TLG showed trends towards shorter PFS in patients with localized disease. In conclusion, detection rate of extranodal MALT lymphoma lesions located in tissues with low/homogeneous physiologic [18F]FDG-uptake is excellent on [18F]FDG PET-CT. When detected, SUVmax of extranodal lesions may predict PFS.

Highlights

Mucosa-associated lymphoid tissue (MALT) lymphoma, known as extranodal marginal zone lymphoma (MZL), involves the mucosa-associated lymphoid tissue and can potentially develop at any mucosal site, most frequently in the stomach, and in the orbit, lung and other tissues [1,2].MALT lymphomas usually follow an indolent clinical course and patients diagnosed with MALT lymphoma usually have a favorable prognosis
As the role of [18F]FDG positron emission tomography—computed tomography (PET-CT) in MALT lymphoma continues to be a subject of debate, in the current study we aimed to summarize our experience in this topic, and use a retrospective cohort of patients to describe and explore the role of semiquantitative PET parameters in staging studies of patients with MALT lymphoma
We report in the current study an association between [18F]FDG-avidity of extranodal lesions and staging variables, including lymphoma’s stage, rates of bulky disease, bone marrow (BM) involvement, and [18F]FDG-avid nodal involvement, associations that were reported in previous studies [8,9]

Summary

Introduction

Mucosa-associated lymphoid tissue (MALT) lymphoma, known as extranodal marginal zone lymphoma (MZL), involves the mucosa-associated lymphoid tissue and can potentially develop at any mucosal site, most frequently in the stomach, and in the orbit, lung and other tissues [1,2].MALT lymphomas usually follow an indolent clinical course and patients diagnosed with MALT lymphoma usually have a favorable prognosis. Mucosa-associated lymphoid tissue (MALT) lymphoma, known as extranodal marginal zone lymphoma (MZL), involves the mucosa-associated lymphoid tissue and can potentially develop at any mucosal site, most frequently in the stomach, and in the orbit, lung and other tissues [1,2]. Due to the large variability in clinical presentation, management of this heterogeneous group of patients is often patient-tailored [3,4]. Patients presenting with localized disease are usually considered for radiotherapy, whereas patients with multiple extranodal lesions or concomitant nodal involvement are referred to watch-and-wait (WW) policy or systemic therapy composed of anti-CD20 antibodies with or without chemotherapy, depending on their symptoms and tumor burden. While 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography—computed tomography (PET-CT) is the preferred imaging modality for staging most lymphoma subtypes [5], it is not considered mandatory for staging MALT lymphomas and other subtypes of MZL [6,7]

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