Bone marrow involvement is not associated with the clinical outcomes of gastric mucosa-associated lymphoid tissue lymphoma

Positron emission tomography/magnetic resonance imaging (PET/MRI) vs. gastroscopy: Can it improve detection of extranodal marginal zone lymphomas of the stomach following H. pylori treatment?

INTRODUCTION

The stomach is the most common site of origin for extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma). Antibiotic eradication of Helicobacter pylori (H. pylori) is the standard first-line treatment, with response assessment being performed by histological evaluation of multiple gastric biopsies.

AREAS COVERED

The objective of this review is to provide an update on results obtained using noninvasive methods, including magnetic resonance imaging (MRI), positron emission tomography combined with computed tomography (PET/CT), and most recently, PET/MRI for the assessment of disease extent and response to treatment in patients with gastric MALT lymphoma.

EXPERT OPINION

While CT is the officially recommended imaging technique, few studies in small cohorts have suggested that diffusion-weighted MRI shows higher sensitivity, also relative to 18 F-FDG PET/CT, for both gastric and nongastric MALT lymphomas. A recent prospective study using PET/MRI with the novel CXCR4-targeting radiotracer 68 Ga-Pentixafor suggested that, for patients with gastric MALT lymphoma after H. pylori eradication, this imaging technique may provide excellent accuracy (97%) for assessment of residual or recurrent disease. Although recent studies on CXCR4-targeting PET and to some extent also diffusion-weighted MRI are promising, there is insufficient evidence to suggest a change in clinical practice.

What you always wanted to know about gastric MALT-lymphoma: a focus on recent developments

The stomach is the most common site of origin for extranodal lymphomas, with extranodal marginal zone B-cell of the mucosa associated lymphoid tissue (MALT-lymphoma) being the predominant subtype. MALT-lymphoma develops in mucosa associated lymphoid structures acquired by infection or chronic antigenic stimuli and may therefore arise in almost any organ of the human body. In spite of histopathologic similarities between various organs upon first glance, recent findings suggest pronounced differences between different sites, with a variety of features specific to gastric MALT-lymphoma. The objective of this review is to sum up the current knowledge on pathogenesis, molecular pathology, clinical presentation and therapeutic approaches to gastric MALT-lymphoma with in-depth discussion of recent developments.

[Diagnosis and Treatment of Gastric Mucosa-associated Lymphoid Tissue Lymphoma]

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients' preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

Depth of Remission Following First-Line Treatment Is an Independent Prognostic Marker for Progression-Free Survival in Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma responding to upfront treatment has an excellent outcome and no further therapy is recommended, even in the presence of residual disease. However, no data exist on the influence of initial depth of remission on progression-free survival (PFS). Methods: We investigated a correlation between PFS and depth of response, categorizing them as complete remission (CR), partial remission (PR) and stable disease (SD) in 137 consecutive patients at the Medical University Vienna. Results: All patients with Helicobacter pylori (H. pylori)-positive, localized disease received H. pylori eradication (70%, 96/137), while the remaining patients were treated with various modalities. The response rate was 67% for the entire collective and 58% for eradication only, with corresponding CR-rates of 48% and 38%. At a median follow-up of 56.2 months, the estimated PFS for the entire cohort was 34.2 months (95% Confidence Interval 16.0–52.4). Responding patients (=CR/PR) had a significantly longer PFS compared to SD (68.3 vs. 17.3 months, p < 0.001). This was also applicable to the eradication only cohort (49.0 vs. 17.3 months, p < 0.001) and remained significant after correction for MALT-IPI. Furthermore, CR significantly prolonged PFS over PR (p = 0.007 entire cohort, p = 0.020 eradication). Conclusions: Remission status correlated significantly with PFS, suggesting depth of remission as prognostic marker for long-term relapse-free survival.

Gastric MALT lymphoma in a population-based study in France: clinical features, treatments and survival

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease, and most available data on gastric MALT lymphoma (GML) come from clinical studies of selected patients treated in centres of excellence.

AIMS

To analyse the clinical features, management and survival of GML patients in a population-based study in France METHODS: All new cases of GML diagnosed between 2002 and 2010 in 11 French areas covered by cancer registries were included. Pathology reports were verified and, if necessary, reviewed by an expert pathologist. All clinical data were retrospectively collected from medical files and analysed using stata V. 14 software.

RESULTS

Four hundred and sixteen patients with confirmed GML (50% male, median age 67 years) were identified. Among them, 44 showed an early transformation into diffuse large B cell lymphoma and were considered to have had an initially missed high-grade lymphoma. At diagnosis, 76% of patients were at stage IE/II, and 24% at stage III/IV of the disease. Helicobacter pylori infection was found in 57% of the patients. Eradication treatment was administered to 76% of patients and complete remission (CR) was obtained in 39%. One hundred and ninety patients received at least one other treatment, including 10 already in CR after eradication. Altogether, CR was obtained in 70% of patients and the 5-year overall survival was 79% (95% CI [75-83]).

CONCLUSIONS

In comparison to clinical series, in the general population, GMLs are more frequently diagnosed at an advanced stage, their clinical management is heterogeneous, and there is a risk of misdiagnosis and overtreatment. These results highlight the necessity of following currently available guidelines in this field.

Prevalence and Implications of Bone Marrow Involvement in Patients with Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Background/Aims

Mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach is an uncommon disease. Bone marrow involvement is reported even in patients with only a mucosal lesion. We evaluated the prevalence and risk factors of marrow involvement and its implications for diagnosis and treatment.

Methods

In total, 132 patients who were diagnosed with gastric MALT lymphoma at the National Cancer Center in Korea between January 2001 and December 2016 were enrolled in the study. The patient data were collected and analyzed retrospectively.

Results

Of the 132 patients, 47 (35.6%) were male, with a median age of 52 years (range, 17 to 81 years). The median follow-up duration was 48.8 months (range, 0.5 to 169.9 months). Helicobacter pylori infection was detected in 82 patients (62.1%). Most patients (80.3%) had stage IE1 according to the modified Ann Arbor staging system. Ninety-two patients underwent bone marrow evaluation, and four patients (4.3%) had marrow involvement. Of these patients, one presented with abdominal lymph node involvement, while the other three had stage IE1 disease if marrow involvement was disregarded. All three patients had no significant symptoms and were monitored after local treatment without evidence of disease aggravation.

Conclusions

Bone marrow involvement was found in 4.3% of the patients with gastric MALT lymphoma. Bone marrow examination may be deferred because marrow involvement does not change the treatment options or outcome in gastric MALT lymphoma confined to the stomach wall.

Endoscopic features and clinical outcomes of colorectal mucosa-associated lymphoid tissue lymphoma

BACKGROUND AND AIMS

Colorectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare disease. The purpose of this study was to investigate the clinical and endoscopic features of colorectal MALT lymphoma.

METHODS

Patients diagnosed with colorectal MALT lymphoma at Asan Medical Center from 2002 to 2016 were eligible. Medical records were reviewed to investigate clinical features and treatment outcomes. Endoscopic pictures were assessed to characterize the endoscopic features of colorectal MALT lymphoma.

RESULTS

A total of 51 patients were enrolled. The median age was 60 years (interquartile range, 55-71), and 21 (41%) were men. Twenty-six patients (51%) were asymptomatic. Forty-four patients (86%) were in early disease stages, namely Lugano stages I, II, and II_E. Endoscopic appearances were classified as 4 distinct types: subepithelial tumor type (26 patients, 51%), polyposis type (10 patients, 20%), epithelial mass type (7 patients, 14%), and ileitis type (8 patients, 16%). The rectum (20 patients, 39%) was the most common location, followed by the ileocecal area (15 patients, 30%). An initial endoscopic impression of lymphoma was made in only 7 patients. Forceps biopsy sampling as the initial tissue acquisition method could histologically diagnose MALT lymphoma in 28 of 35 patients (80%). Polypectomy as the initial histologic diagnosis could diagnose MALT lymphoma in 16 of 16 patients. Progression-free and overall survival rates at 5 years were 92% and 94%, respectively.

CONCLUSIONS

Colorectal MALT lymphomas show various endoscopic appearances, complicating the endoscopic suspicion of colorectal MALT lymphoma. The prognosis of colorectal MALT lymphoma was excellent.