The unique biology and treatment of primary mediastinal B-cell lymphoma

[Progress in treatment of primary mediastinal large B-cell lymphoma]

Primary mediastinal large B-cell lymphoma (PMBCL) is an aggressive B-cell lymphoma originating from the thymus, which has different clinical and biological characteristics from diffuse large B-cell lymphoma, NOS. PMBCL tends to occur in young women, usually presenting as a large anterior mediastinal mass. Most patients are in stage Ⅰ-Ⅱ at the time of presentation. There is no standard prognostic scoring system for PMBCL. Immunochemotherapy is commonly used in the treatment of PMBCL, but the optimal first-line treatment has not been determined, and the status of radiotherapy is controversial. The value of PET-CT guided therapy needs to be further verified. Relapsed/refractory PMBCL has a poor prognosis, while novel therapies such as PD-1 inhibitors, brentuximab vedotin, and CAR-T can help improve survival in these patients.

A case of suspected primary mediastinal large B-cell lymphoma: An uncommon cause of sudden death

Primary mediastinal large B-cell lymphoma (PMLBCL) is an aggressive tumor originating from thymic B-cells. Clinically, it presents with general signs such as cough, chest pain and dyspnea. Although these symptoms are not specific, they are severe enough to reveal the disease. We report an autopsy case of a 25-year-old man, with a recent past history of cough and dyspnea, for which he consulted twice the emergency department and no diagnosis was made. He presented to the Emergency Unit, with a sudden onset of a dyspnea followed by a loss of consciousness. He was shortly declared dead after, a medico-legal autopsy was requested. On external examination, no traumatic lesions on the body were found, an important cyanosis of the face and ears, was, however, found. On autopsy, a mediastinal mass was found, measuring 19 cm × 25 cm and weighing 600 g, extending to the infra-hyoid region and to the thoracic cage and infiltrating the pericardium. Trachea had a necrotic mucosa with a partially obstructive lymph node mass. The diagnosis of a primary mediastinal large B-cell lymphoma was suspected based on pathological and immunohistochemical findings. The cause of death was finally attributed to respiratory failure due to this tumor.

CD30+ Lymphoproliferative Disorders as Potential Candidates for CD30-Targeted Therapies

CONTEXT.—

In the early 1980s, a monoclonal antibody termed Ki-1 was developed against a cell line derived from a patient with Hodgkin lymphoma. This antibody detected a limited number of benign activated lymphocytes in lymphoid tissue, whereas in Hodgkin lymphoma it appeared to be nearly specific for Reed-Sternberg cells and their mononuclear variants. Subsequent studies showed that Ki-1 expression defined a new type of lymphoma that was later designated anaplastic large cell lymphoma with or without anaplastic large cell kinase expression/translocation. In the past 30 years, numerous new lymphoma entities have been defined, many of which are variably positive for CD30. Many virally transformed lymphoproliferative disorders are also frequently positive for CD30.

OBJECTIVE.—

To illustrate the broad spectrum of CD30+ hematologic malignancies and to provide an update of CD30-targeted therapies.

DATA SOURCES.—

Personal experiences and published works in PubMed.

CONCLUSIONS.—

Because of its low expression in normal tissue, CD30 was studied as a therapeutic target for many years. However, the first functional humanized antibody against CD30 was developed only about 10 years ago. Brentuximab vedotin is a humanized anti-CD30 antibody linked to a cytotoxin, and was approved by the US Food and Drug Administration in 2012 for treating refractory Hodgkin lymphoma and anaplastic large cell lymphoma. Since then, the list of Food and Drug Administration-approved CD30-targeted hematologic malignancies has grown. Recently, the therapies using tumor antigen-specific chimeric antigen receptor T cells targeting CD30 have incited a great deal of enthusiasm and are studied in clinical trials.

[Cardiovascular complications in pregnant woman with Primary Mediastinal B-Cell Lymphoma]

A 26-year-old pregnant woman with 29 weeks of gestational age reported two months of cough, dyspnea, orthopnea, and palpitations. Chest tomography revealed a 10x12cm solid mass in the right lung. Echocardiography showed that the tumor compromised the right atrium and ventricle, and was diagnosed by transcutaneous biopsy as Primary Mediastinal B-Cell Lymphoma (PMCBL). The patient presented 2:1 atrial flutter, sinus bradycardia, and ectopic atrial bradycardia. Due to the rapid poor evolution, it was decided to terminate the pregnancy by cesarean section and start chemotherapy, after which the cardiovascular complications resolved. PCML is a very rare lymphoma that can affect pregnant women in any trimester, its symptoms are related to its rapid growth and compromise of the heart, causing various cardiovascular manifestations (heart failure, pericardial effusion, cardiac arrhythmias). PCMLC is characteristically chemosensitive and has a good prognosis.

Prognostic significance of clinical characteristics and 18Fluorodeoxyglucose-positron emission tomography/computed tomography quantitative parameters in patients with primary mediastinal B-cell lymphoma

Objective

Primary mediastinal B-cell lymphoma (PMBCL) lacks standard treatment regimens. This study aimed to identify the disease’s clinical features and prognostic factors.

Methods

This retrospective study included 56 patients with PMBCL. Patient demographic details and clinicopathological characteristics were summarized, and their effects on progression-free survival (PFS) and overall survival (OS) were analyzed.

Results

The median patient age was 29 years (range, 14–56). Twenty-two patients received DA-EPOCH-R (dose-adjusted etoposide, vincristine, and doxorubicin for 96 hours with bolus doses of cyclophosphamide and oral prednisone, as well as rituximab), and 34 patients received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). Clinical/laboratory parameters, overall response rates, and 5-year PFS and OS rates did not differ between the treatment groups. Kaplan–Meier analysis indicated that late-stage disease and a higher International Prognostic Index (IPI) were associated with shorter PFS and OS. Furthermore, patients with B symptoms and first-line treatment non-responders exhibited worse OS. ¹⁸Fluorodeoxyglucose-positron emission tomography/computed tomography quantitative parameters, such as higher metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were corrected with shorter PFS.

Conclusions

This study revealed that stage IV disease, higher IPI, and B symptoms were poor prognostic factors in patients with PMBCL. Significantly, higher MTV and TLG portended worse PFS.

Primary Mediastinal B-Cell Lymphoma: A 2021 Update on Genetics, Diagnosis, and Novel Therapeutics

Primary mediastinal large B-cell lymphoma (PMBCL) is an aggressive B-cell lymphoma arising from thymic B-cells having clinicopathologic features distinct from systemic diffuse large B-cell lymphoma (DLBCL). PMBCL comprises 2% to 4% of all non-Hodgkin lymphomas (NHL), 7% of DLBCL and seen predominantly in young females with a median age of 35 years at diagnosis. The annual incidence of PMBCL is 0.4 per million with a 5-year survival rate exceeding 70% with improving supportive care and genetic characterization of the disease. Pathogenesis involves dysregulation of Janus kinase-signal transducer and activator of transcription (JAK-STAT), nuclear factor-kB (NF-kB) pathways and amplification of the 9p24.1 region of chromosome 9. PMBCL patients have a prolonged life expectancy necessitating the need for treatment approaches that are based on maximizing cure with minimal long-term toxicity. Due to rarity and its recognition as a distinct entity, therapeutic decisions are guided by clinical presentation, clinician and center experience, and analysis of patients with PMBCL within DLBCL registries. Historically R-CHOP has been the usual first line treatment for PMBCL followed by involved site radiotherapy (ISRT), however clinical practice varies across centers with emerging consensus to avoid upfront RT by utilizing dose intense regimens (DA-EPOCH-R) in younger and fit patients. Prognosis of relapsed refractory PMBCL not responding to salvage chemotherapy is dismal, however there are many emerging options including Brentuximab Vedotin, immune check point inhibitors and chimeric antigen receptor T-cell therapy. In this article, we focus on the pathogenesis, current and evolving treatments, and provide recommendations for optimal management of patients with PMBCL.

PD-1 and LAG-3 Checkpoint Blockade: Potential Avenues for Therapy in B-Cell Lymphoma

The dependence of cancer on an immunotolerant tumor microenvironment (TME) is well established. Immunotherapies that overcome tumor-induced immune suppression have been central to recent advancements in oncology. This is highlighted by the success of agents that interrupt PD-1 mediated immune suppression in a range of cancers. However, while PD-1 blockade has been paradigm-shifting in many malignancies, the majority of cancers show high rates of primary resistance to this approach. This has led to a rapid expansion in therapeutic targeting of other immune checkpoint molecules to provide combination immune checkpoint blockade (ICB), with one such promising approach is blockade of Lymphocyte Activation Gene 3 (LAG-3). Clinically, lymphoproliferative disorders show a wide spectrum of responses to ICB. Specific subtypes including classical Hodgkin lymphoma have demonstrated striking efficacy with anti-PD-1 therapy. Conversely, early trials of ICB have been relatively disappointing in common subtypes of Non-Hodgkin lymphoma. In this review, we describe the TME of common lymphoma subtypes with an emphasis on the role of prominent immune checkpoint molecules PD-1 and LAG3. We will also discuss current clinical evidence for ICB in lymphoma and highlight key areas for further investigation where synergistic dual checkpoint blockade of LAG-3 and PD-1 could be used to overcome ICB resistance.

Novel Therapies Potentially Available for Pediatric B-Cell Non-Hodgkin Lymphoma

Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and primary mediastinal B-cell lymphoma are the most common aggressive pediatric mature B-cell non-Hodgkin lymphomas (B-NHLs). Despite excellent survival with current chemotherapy regimens, therapy for Burkitt lymphoma and DLBCL has a high incidence of short- and long-term toxicities. Patients who experience relapse generally have a very poor prognosis. Therefore, novel approaches using targeted therapies to reduce toxicities and improve outcomes in the relapse setting are needed. The addition of rituximab, a monoclonal antibody against CD20, to upfront therapy has improved survival outcomes for high-risk patients and may allow decreased total chemotherapy in those with low-risk disease. Antibody-drug conjugates have been combined with chemotherapy in relapsed/refractory (R/R) NHL, and multiple antibody-drug conjugates are in development. Additionally, bispecific T-cell-engaging antibody constructs and autologous CAR T-cells have been successful in the treatment of R/R acute leukemias and are now being applied to R/R B-NHL with some successes. PD-L1 and PD-L2 on tumor cells can be targeted with checkpoint inhibitors, which restore T-cell-mediated immunity and antitumor responses and can be added to conventional chemotherapy and immune-directed therapies to augment responses. Lastly, trials of small molecule inhibitors targeting cell signaling pathways in NHL subtypes are underway. This article reviews many of the targeted therapies under development that could be considered for future trials in R/R pediatric mature B-NHL.

Camrelizumab Plus Gemcitabine, Vinorelbine, and Pegylated Liposomal Doxorubicin in Relapsed/Refractory Primary Mediastinal B-Cell Lymphoma: A Single-Arm, Open-Label, Phase II Trial

PURPOSE

Patients with relapsed/refractory primary mediastinal B-cell lymphoma (rrPMBCL) represent a particularly challenging population to treat, with few life-saving treatment options in the context of a dismal prognosis.

PATIENTS AND METHODS

In this open-label, single-arm, phase II study, the safety and efficacy of combined regimen of chemotherapy consisting of gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD) plus anti-PD-1 antibody camrelizumab was assessed in rrPMBCL. Patients received chemo-immunotherapy every 3 weeks until the second confirmed complete response (CR) or up to 12 cycles, followed by camrelizumab monotherapy for up to 1 year. The primary endpoints were objective response rate (ORR) and safety.

RESULTS

Twenty-seven response evaluable patients were enrolled, who received a median of three first-line therapies, 59% with bulky disease. The ORR was 74%, including 56% with a CR. A median time of 1.7 months to response was observed, with 78% exhibiting tumor shrinkage at the first evaluation. After 24.8 months median follow-up, the median duration of response was not reached, with a 65% 2-year estimated response rate. Thirteen responders remained in sustained complete remission. Estimated 24-month progression-free survival and overall survival rates were 48.2% and 81.5%, respectively. Any grade and grade 3 treatment-related adverse events (AE) occurred in 93% and 33% of patients, respectively; with no grade 4 or 5 AEs. Baseline levels of IL10, IFNγ, and soluble Fas were associated with objective response.

CONCLUSIONS

Camrelizumab plus GVD chemotherapy offers a potent option as life-saving chemo-immunotherapy with promising efficacy and a manageable safety profile for patients with rrPMBCL, especially with bulky aggressive disease.

Prognostic factors, therapeutic approaches, and distinct immunobiologic features in patients with primary mediastinal large B-cell lymphoma on long-term follow-up

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare and distinct subtype of diffuse large B-cell lymphoma (DLBCL) without prognostic factors or a single standard of treatment clearly defined. In this study we performed retrospective analysis for clinical outcomes of 166 patients with PMBCL. In overall PMBCL, higher International Prognostic Index, stage, Ki-67 proliferation index, and positron emission tomography (PET) maximum standardized uptake values (SUVmax) at diagnosis were significantly associated with poorer survival, whereas MUM1 expression and higher peripheral blood lymphocyte/monocyte ratios were significantly associated with better survival. Patients who received R-HCVAD or R-EPOCH had better clinical outcome than did those who received the standard treatment R-CHOP. Treatment response and end-of-treatment PET SUVmax had remarkable correlations with survival outcome. In patients with refractory or relapsed PMBCL, stem cell transplant significantly improved overall survival. PMBCL had distinct gene expression signatures compared with overall DLBCL–NOS but not with DLBCL with PD-L1/PD-L2 amplification. PMBCL also showed higher PD-L2 expression in B-cells, lower PD-1 expression in T-cells, and higher CTLA-4 expression in T-cells and distinct miRNA signatures compared with DLBCL-NOS. The prognostic factors, effectiveness of treatment, transcriptional and epigenetic signatures, and immunologic features revealed by this study enrich our understanding of PMBCL biology and support future treatment strategy.

Primary Mediastinal Large B-Cell Lymphoma: A Review for Radiologists

OBJECTIVE. The purpose of this article is to provide a primer for radiologists focused on integrating the radiologic, pathologic, and clinical features of primary mediastinal large B-cell lymphoma (PMLBCL). CONCLUSION. PMLBCL is a unique subtype of lymphoma that poses diagnostic and therapeutic challenges to the fields of radiology and oncology. Knowledge of this distinctive clinical-pathologic entity and its associated imaging and clinical features is critical for radiologists.