How can we assess and measure prognosis for MALT lymphoma? A review of current findings and strategies

ABSTRACT

Introduction

: MALT (mucosa associated lymphoid tissue) lymphoma is a distinct type of B-cell lymphoma characterized by extranodal manifestation and an indolent clinical course with 10-year survival rates up to 90%. However, transformation to aggressive lymphoma may occur and treatment is indicated in case of symptomatic or progressive disease.

Areas covered

: This review covers clinical and biological features potentially related to prognosis and outcome of MALT lymphoma patients, as well as available prognostic tools and risk stratification systems with a focus on the MALT-IPI (international prognostic index) and the POD24 (progression of disease at 24 months) cohort. In addition, we address the role of watch-and-wait, the importance of defining the optimal time point for treatment initiation and the relevance of depth of remission, which appear to be some of the central questions for physicians involved in the care of MALT lymphoma patients. A computerized database search using PubMed® was performed to identify available publications on prognostic factors and risk stratification tools in MALT lymphoma.

Expert opinion

: Despite the development of disease-specific risk stratification systems, there is no clear concept how to measure prognosis and tailor treatment. Careful observation of the individual clinical course is essential to assess the optimal time point of treatment initiation and avoid overtreatment, particularly in patients with disseminated disease. In addition, early detection of patients with histological transformation is necessary, as these patients face a poor prognosis.

KEYWORDS:

• MALT lymphoma
• extranodal lymphoma
• MALT-IPI
• pod24
• helicobacter pylori

Article highlights

• Clinical factors that have been suggested to influence outcome include disseminated disease, nodal involvement, bone marrow infiltration, elevation of LDH and advanced age currently defined as 70+ years for MALT lymphoma.

• Translocation t(11;18)(q21;q21)/API2-MALT1 has been associated with resistance of gastric MALT lymphoma to Helicobacter pylori (H. pylori) eradication, but routine assessment at initial diagnosis is not universally recommended in everyday practice as antibiotics should be the first-line treatment irrespective of translocation status.

• No molecular or genetic markers other than t(11;18)(q21;q21) are currently of relevance in clinical practice. Data of sequencing studies are awaited.

• The MALT-IPI clinical score has been developed specifically for MALT lymphoma patients and uses age ≥ 70 years, Ann Arbor stage IIIE or IV and elevated LDH as factors to build risk groups for EFS (event-free survival), PFS (progression-free survival), CSS (cause-specific survival) and OS (overall survival).

• POD24, defined as progression of disease within 24 months after treatment initiation, is a cohort of patients with poor prognosis for all kinds of indolent lymphoma. These patients warrant specific attention.

• Histological transformation to DLBCL (diffuse large B-cell lymphoma) results in significant worsening of prognosis, thus, re-biopsy of new or rapidly growing lesion is strictly recommended.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.