Splenic marginal zone lymphoma: A US population‐based survival analysis (1999‐2016)

Marginal zone lymphomas: a consensus practice statement from the Australasian Lymphoma Alliance

Marginal zone lymphomas (MZLs) are a rare, indolent group of non-Hodgkin lymphomas with different diagnostic, genetic and clinical features and therapeutic implications. The most common is extranodal MZL of mucosa-associated lymphoid tissue, followed by splenic MZL and nodal MZL. Patients with MZL generally have good outcomes with long survival rates but frequently have a relapsing/remitting course requiring several lines of therapy. The heterogeneous presentation and relapsing course present the clinician with several diagnostic and therapeutic challenges. This position statement presents evidence-based recommendations in the setting of Australia and New Zealand.

Time Trend Analysis of Splenectomy for Splenic Marginal Zone Lymphoma: Declining Surgery, Promising Survival

BACKGROUND

The purpose of current study was to examine the incidence, characteristics, treatment, and survival of splenic marginal zone lymphoma (SMZL).

METHODS

Using SEER-18 database, patients diagnosed with SMZL between 2000 and 2018 were included. Effect of splenectomy on survival was evaluated after balancing the confounding factors by propensity score matching. Rates of splenectomy and 1-year relative survival were calculated for each year. A logistic regression model identified factors related to splenectomy, and a Cox regression model assessed factors linked to overall survival (OS).

RESULTS

A total of 2790 patients with SMZL were analyzed. The majority were older than 60 years, female, and white. The age-adjusted incidence of SMZL was 0.17/100,000 person-years, with higher incidence in males. Incidence increased by 0.68%/year and peaked at 80-84 years for both genders. The SMZL-specific survival rates at 3 and 5 years were 89.6% and 85.3%, respectively. Meanwhile, the relative survival rates for the same periods were 88.6% and 85.9%, respectively. Splenectomy patients were more likely to be younger, male, and diagnosed with early-stage disease. Despite the decreasing utilization rate of splenectomy from 59.4% in 2000 to 16.2% in 2018, the 1-year relative survival rate remained relatively stable with minor fluctuations over time. Whether or not the patient underwent splenectomy was not found to be a significant prognostic indicator for OS.

CONCLUSIONS

Our study demonstrated a decreasing use of splenectomy but a relatively stable survival in patients with SMZL, highlighting the urgency to better understand the role of splenectomy and its associated outcomes.

Sclerotic marginal zone lymphoma: A case report

BACKGROUND

Marginal zone lymphoma (MZL) is an indolent non-Hodgkin B cell lymphoma with various architectural pattern including perifollicular, follicular colonization, nodular, micronodular, and diffuse patterns. A sclerotic variant has not been previously reported and represents a diagnostic pitfall.

CASE SUMMARY

A 66-year-old male developed left upper extremity swelling. Chest computed tomography (CT) in September 2020 showed 14 cm mass in left axilla. Needle core biopsy of axillary lymph node showed sclerotic tissue with atypical B lymphoid infiltrate but was non-diagnostic. Excisional biopsy was performed for diagnosis and showed extensive fibrosis and minor component of infiltrating B cells. Flow cytometry showed a small population of CD5-, CD10-, kappa restricted B cells. Monoclonal immunoglobulin heavy chain and light chain gene rearrangement were identified. Upon being diagnosed with MZL, patient was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone and achieved complete remission by positron emission tomography/CT.

CONCLUSION

This is an important case report because by morphology this case could have easily been overlooked as non-specific fibrosis with chronic inflammation representing a significant diagnostic pitfall. Moreover, this constitutes a new architectural pattern. While sclerotic lymphomas have rarely been described (often misdiagnosed as retroperitoneal fibrosis), we do not know of any cases describing this architectural presentation of MZL.

Splenic marginal zone lymphoma in Sweden 2000-2020: Increasing rituximab use and better survival in the elderly

The treatment of splenic marginal zone lymphoma is debated: splenectomy (the old standard-of-care) is better than chemotherapy but maybe not better than rituximab-containing treatment. We examined all 358 patients diagnosed with splenic marginal zone lymphoma in Sweden 2000-2020. The median overall survival was 11.0 years. The median age was 73 years; 61% were women. Age was the only independently prognostic clinical characteristic. Eighty-six patients were started on wait-and-watch, 90 rituximab monotherapy, 47 rituximab-chemotherapy, 88 splenectomy, 37 chemotherapy, and 10 both systemic therapy and splenectomy. Overall survival was inferior in patients treated with chemotherapy, but equal in patients treated with rituximab, rituximab-chemotherapy and splenectomy. Patients treated with both systemic therapy and splenectomy showed good outcome, suggesting that surgery can be safely reserved for nonresponders. After adjustment for age, survival did not differ between patients started on wait-and-watch and those treated with splenectomy or rituximab-containing therapy. Over time, rituximab use and survival increased in patients ≥73 years. This is, to our knowledge, the largest population-based study of splenic marginal zone lymphoma patients treated with upfront rituximab. We conclude that wait-and-watch remains the most reasonable option in asymptomatic splenic marginal zone lymphoma patients. Symptomatic patients should be offered single-agent rituximab in first line.

Low-risk HPLLs/ABC score patients with splenic marginal zone lymphoma can be safely managed without treatment: Results from a prospective Spanish study

The aims of our study were to analyse compliance with the 2014 GELTAMO SMZL Guidelines, in patients with splenic marginal zone lymphoma (SMZL), and to evaluate the outcome according to the HPLLs/ABC-adapted therapeutic strategy. Observational prospective multicenter study of 181 SMZL patients diagnosed between 2014 and 2020. Lymphoma-specific survival (LSS), composite event-free survival (CEFS) and response rates were assessed. 57% of the 168 patients included in the analysis followed the Guidelines. The overall response rate was higher in the rituximab chemotherapy and in the rituximab arms compared with the splenectomy arm (p < 0.001). The 5-year overall survival was 77% and the 5-year LSS of 93%. There were no differences in the 5-year LSS according to the treatment received (p = 0.68). The 5-year CEFS in the overall series was 45%, and there were significant differences between scores A and B (p = 0.036). There were no significant differences when comparing LSS and progression-free survival in patients treated with rituximab or rituximab chemotherapy at diagnosis or after observation. Our data support HPLLs/ABC score as a practical tool for the management of SMZL, observation as the best approach for patients in group A and rituximab as the best treatment for group B.

Marginal zone lymphomas

The three main types of marginal zone lymphoma (MZL), recognized by the current lymphoma classifications are the extranodal MZL of mucosa-associated lymphoid tissue, the splenic MZL, and the nodal MZL. They share some karyotype lesions (trisomies of chromosomes 3 and 18, deletions at 6q23), and alterations of the nuclear factor kappa B (NFkB) pathway are also common in all of them. However, they differ in the presence of recurrent translocations, mutations affecting the Notch signaling pathway (NOTCH2 and less commonly NOTCH1), the transcription factors Kruppel-like factor 2 (KLF2) or the receptor-type protein tyrosine phosphatase delta (PTPRD). This review summarizes the most recent and significant advances in our understanding of the epidemiology, genetics, and biology of MZLs and outlines the current principles of the standard management of MZL at different anatomic sites.

Incidental Splenic Marginal Zone Lymphoma With Extreme Macrocytosis After Hydroxyurea Use: A Case Report

Splenic marginal zone lymphoma (SMZL) is a low-grade mature B-cell lymphoma that typically presents in the form of splenomegaly and lymphocytosis. The diagnosis is traditionally made through splenic histology, the presence of circulating villous lymphocytes, or bone marrow biopsy. Its treatment can be in the form of chemotherapy, such as rituximab, or active surveillance. This case presentation discusses a 76-year-old female with a long history of hydroxyurea use for an unknown reason presenting with atypical symptoms requiring bone marrow biopsy to diagnose SMZL. This unique case demonstrates the importance of further research and studies into atypical SMZL presentations and hydroxyurea's potential in precipitating secondary malignancies.

Genetic and phenotypic attributes of splenic marginal zone lymphoma

Splenic marginal zone B-cell lymphoma (SMZL) is a heterogeneous clinico-biological entity. The clinical course is variable, multiple genes are mutated with no unifying mechanism, and essential regulatory pathways and surrounding microenvironments are diverse. We sought to clarify the heterogeneity of SMZL by resolving different subgroups and their underlying genomic abnormalities, pathway signatures, and microenvironment compositions to uncover biomarkers and therapeutic vulnerabilities. We studied 303 SMZL spleen samples collected through the IELSG46 multicenter international study (NCT02945319) by using a multiplatform approach. We carried out genetic and phenotypic analyses, defined self-organized signatures, validated the findings in independent primary tumor metadata and in genetically modified mouse models, and determined correlations with outcome data. We identified 2 prominent genetic clusters in SMZL, termed NNK (58% of cases, harboring NF-κB, NOTCH, and KLF2 modules) and DMT (32% of cases, with DNA-damage response, MAPK, and TLR modules). Genetic aberrations in multiple genes as well as cytogenetic and immunogenetic features distinguished NNK- from DMT-SMZLs. These genetic clusters not only have distinct underpinning biology, as judged by differences in gene-expression signatures, but also different outcomes, with inferior survival in NNK-SMZLs. Digital cytometry and in situ profiling segregated 2 basic types of SMZL immune microenvironments termed immune-suppressive SMZL (50% of cases, associated with inflammatory cells and immune checkpoint activation) and immune-silent SMZL (50% of cases, associated with an immune-excluded phenotype) with distinct mutational and clinical connotations. In summary, we propose a nosology of SMZL that can implement its classification and also aid in the development of rationally targeted treatments.

CD5-Negative, CD10-Negative Low-Grade B-Cell Lymphoproliferative Disorders of the Spleen

CD5-negative, CD10-negative low-grade B-cell lymphoproliferative disorders (CD5-CD10-LPD) of the spleen comprise a fascinating group of indolent, neoplastic, mature B-cell proliferations that are essential to accurately identify but can be difficult to diagnose. They comprise the majority of B-cell LPDs primary to the spleen, commonly presenting with splenomegaly and co-involvement of peripheral blood and bone marrow, but with little to no involvement of lymph nodes. Splenic marginal zone lymphoma is one of the prototypical, best studied, and most frequently encountered CD5-CD10-LPD of the spleen and typically involves white pulp. In contrast, hairy cell leukemia, another well-studied CD5-CD10-LPD of the spleen, involves red pulp, as do the two less common entities comprising so-called splenic B-cell lymphoma/leukemia unclassifiable: splenic diffuse red pulp small B-cell lymphoma and hairy cell leukemia variant. Although not always encountered in the spleen, lymphoplasmacytic lymphoma, a B-cell lymphoproliferative disorder consisting of a dual population of both clonal B-cells and plasma cells and the frequent presence of the MYD88 L265P mutation, is another CD5-CD10-LPD that can be seen in the spleen. Distinction of these different entities is possible through careful evaluation of morphologic, immunophenotypic, cytogenetic, and molecular features, as well as peripheral blood and bone marrow specimens. A firm understanding of this group of low-grade B-cell lymphoproliferative disorders is necessary for accurate diagnosis leading to optimal patient management.

NOTCH signaling in the pathogenesis of splenic marginal zone lymphoma-opportunities for therapy

NOTCH signaling is a highly conserved pathway mediated by four receptors (NOTCH 1-4) playing critical functions in proliferation, differentiation, and cell death. Under physiologic circumstances, NOTCH2 is a key regulator in marginal zone differentiation and development. Over the last decade, growing data demonstrated frequent NOTCH2 mutations in splenic marginal zone lymphoma (SMZL) underscoring its critical role in the pathogenesis of this disease. Moreover, NOTCH2 specificity across studies supports the rationale to assess its value as a diagnosis biomarker in a disease without pathognomonic features. These data make NOTCH signaling an appealing target for drug discovery in SMZL; however, prior efforts attempting to manipulate this pathway failed to demonstrate meaningful clinical benefit, or their safety profile prevented further development. In this review, we discuss the current knowledge of NOTCH implications in the pathogenesis and as a potential druggable target in SMZL.

Superior outcome for splenectomised patients in a population-based study of splenic marginal zone lymphoma in Sweden

Splenic marginal zone lymphoma (SMZL) is a rare low-grade B-cell lymphoma where associations with viral hepatitis and autoimmune and inflammatory diseases (AID) have been indicated. We aimed at assessing the prevalence of viral hepatitis and AID at SMZL diagnosis and outcome by treatment in a Swedish population-based study. A total of 277 SMZL patients registered in the Swedish Lymphoma Register in 2007-2017 were included. A history of viral hepatitis was reported in five (2%) patients and AID prior to SMZL in 72/240 (30%) patients. Treatment was given up front for 207 (75%) patients. Splenectomy with or without systemic treatment was performed in 119 (57%) and was associated with statistically significantly better overall survival [hazard ratio, HR = 0·47 (95% confidence interval, CI: 0·23-0·93), P = 0·03] and progression-free survival (HR = 0·55, 95% CI: 0·35-0·86, P = 0·008) compared to non-splenectomised patients in multivariable analyses. The up-front splenectomised group was younger and generally had a lower Ann Arbor stage, but also more frequently B symptoms and high lactate dehydrogenase than the non-splenectomised group. Viral hepatitis and AID history did not affect SMZL outcome. We report high incidence of AIDs and low incidence of viral hepatitis in this population-based study of SMZL. Splenectomy up front was associated with a favourable outcome.

Rare lymphomas in routine practice - Treatment and outcome in marginal zone lymphoma in the prospective German Tumour Registry Lymphatic Neoplasms

Owing to its heterogeneity and rarity, management of disseminated marginal zone B‐cell lymphoma (MZL) remains largely understudied. We present prospective data on choice of systemic treatment and survival of patients with MZL treated in German routine practice. Of 175 patients with MZL who had been documented in the prospective clinical cohort study Tumour Registry Lymphatic Neoplasms (NCT00889798) collecting data on systemic treatment, 58 were classified as extranodal MZL of mucosa‐associated lymphoid tissue (MALT) and 117 as non‐MALT MZL. We analyzed the most commonly used first‐line and second‐line chemo(immuno)therapies between 2009 and 2016 and examined objective response rate (ORR), progression‐free survival (PFS), overall survival (OS) and prognostic factors for survival. Compared to patients with MALT MZL, those with non‐MALT MZL more often presented with bone marrow involvement (43% vs. 14%), Ann Arbor stage III/IV (72% vs. 57%) and were slightly less often in good general condition (ECOG = 0; 41% vs. 47%). In German routine practice, rituximab‐bendamustine for a median of 6 cycles was the most frequently used first‐line (76%) and second‐line treatment (36%), with no major differences between MZL subtypes. The ORR for patients encompassing any positive response was 81%. For patients with MALT and non‐MALT MZL, respectively, 5‐years PFS was 69% (95% CI 52%–81%) and 66% (95% CI 56%–75%), 5‐years OS 79% (95% CI 65%–89%) and 75% (95% CI 66%–83%). Cox proportional hazards models showed a significantly increased risk of mortality for higher age in all patient groups. Our prospective real world data give valuable insights into the management and outcome of non‐selected patients with MZL requiring systemic treatment and can help optimize therapy recommendations.