Identification of Very Low-Risk Subgroups of Patients with Primary Mediastinal Large B-Cell Lymphoma Treated with R-CHOP

A predictive model for HIV-related lymphoma

OBJECTIVES

To address the paucity of HIV-related lymphoma (HRL)-specific prognostic scores for the Japanese population by analyzing domestic cases of HRL and constructing a predictive model.

DESIGN

A single-center retrospective study coupled with a review of case reports of HRL.

METHODS

We reviewed all patients with HRL treated at our hospital between 2007 and 2023 and conducted a comprehensive search for case reports of HRL from Japan using public databases. A multivariate analysis for overall survival (OS) was performed using clinical parameters, leading to the formulation of the HIV-Japanese Prognostic Index (HIV-JPI).

RESULTS

A total of 19 patients with HRL were identified in our institution, whereas the literature review yielded 44 cases. In the HIV-JPI, a weighted score of 1 was assigned to the following factors: age at least 45 years, HIV-RNA at least 8.0×10 4  copies/ml, Epstein-Barr virus-encoded small RNA positivity, and Ann Arbor classification stage IV. The overall score ranged from 0 to 4. We defined the low-risk group as scores ranging from 0 to 2 and the high-risk group as scores ranging from 3 to 4. The 3-year OS probability of the high-risk group [30.8%; 95% confidence interval (CI): 9.5-55.4%) was significantly poorer than that of the low-risk group (76.8%; 95% CI: 52.8-89.7%; P  < 0.01).

CONCLUSION

This retrospective analysis established pivotal prognostic factors for HRL in Japanese patients. The HIV-JPI, derived exclusively from Japanese patients, highlights the potential for stratified treatments and emphasizes the need for broader studies to further refine this clinical prediction model.

[Chinese expert consensus on the diagnosis and management of primary mediastinal large B-cell lymphoma (2024)]

Primary mediastinal large B-cell lymphoma (PMBL) is an aggressive B-cell lymphoma that is thought to arise from thymic (medullary) B cells and has unique clinicopathologic and molecular features. In recent years, the understanding of the pathogenesis and treatment of PMBL has been updated to varying degrees, particularly in the area of new drug therapy. In order to improve the diagnosis and treatment of PMBL in China, the Lymphocyte Disease Group of the Chinese Medical Association (CMA) and the Anti-Lymphoma Alliance of the Chinese Society of Clinical Oncology (CSCO) commissioned a group of experts to formulate this consensus.

Genetic Characterization of Primary Mediastinal B-Cell Lymphoma: Pathogenesis and Patient Outcomes

PURPOSE

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare aggressive lymphoma predominantly affecting young female patients. Large-scale genomic investigations and genetic markers for risk stratification are lacking.

PATIENTS AND METHODS

To elucidate the full spectrum of genomic alterations, samples from 340 patients with previously untreated PMBCL were investigated by whole-genome (n = 20), whole-exome (n = 78), and targeted (n = 308) sequencing. Statistically significant prognostic variables were identified using a multivariable Cox regression model and confirmed by L1/L2 regularized regressions.

RESULTS

Whole-genome sequencing revealed a commonly disrupted p53 pathway with nonredundant somatic structural variations (SVs) in TP53-related genes (TP63, TP73, and WWOX) and identified novel SVs facilitating immune evasion (DOCK8 and CD83). Integration of mutation and copy-number data expanded the repertoire of known PMBCL alterations (eg, ARID1A, P2RY8, and PLXNC1) with a previously unrecognized role for epigenetic/chromatin modifiers. Multivariable analysis identified six genetic lesions with significant prognostic impact. CD58 mutations (31%) showed the strongest association with worse PFS (hazard ratio [HR], 2.52 [95% CI, 1.50 to 4.21]; P < .001) and overall survival (HR, 2.33 [95% CI, 1.14 to 4.76]; P = .02). IPI high-risk patients with mutated CD58 demonstrated a particularly poor prognosis, with 5-year PFS and OS rates of 41% and 58%, respectively. The adverse prognostic significance of the CD58 mutation status was predominantly observed in patients treated with nonintensified regimens, indicating that dose intensification may, to some extent, mitigate the impact of this high-risk marker. By contrast, DUSP2-mutated patients (24%) displayed durable responses (PFS: HR, 0.2 [95% CI, 0.07 to 0.55]; P = .002) and prolonged OS (HR, 0.11 [95% CI, 0.01 to 0.78]; P = .028). Upon CHOP-like treatment, these patients had very favorable outcome, with 5-year PFS and OS rates of 93% and 98%, respectively.

CONCLUSION

This large-scale genomic characterization of PMBCL identified novel treatment targets and genetic lesions for refined risk stratification. DUSP2 and CD58 mutation analyses may guide treatment decisions between rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone and dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab.

[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 nomogram for predicting the rapid progression of diffuse large B-cell lymphoma established by combining baseline PET/CT total metabolic tumor volume, lesion diffusion, and TP53 mutations

OBJECTIVES

This study aimed to integrate positron emission tomography/computed tomography (PET/CT) metrics and genetic mutations to optimize the risk stratification for diffuse large B-cell lymphoma (DLBCL) patients.

METHODS

The data of 94 primary DLBCL patients with baseline PET/CT examination completed in the Shandong Cancer Hospital and Institute (Jinan, China) were analyzed to establish a training cohort. An independent cohort of 45 DLBCL patients with baseline PET/CT examination from other hospitals was established for external validation. The baseline total metabolic tumor volume (TMTV) and the largest distance between two lesions (Dmax) standardized by patient body surface area (SDmax) were calculated. The pretreatment pathological tissues of all patients were sequenced by a lymphopanel including 43 genes.

RESULTS

The optimal TMTV cutoff was 285.3 cm3 and the optimal SDmax cutoff was 0.135 m-1 . TP53 status was found as an independent predictive factor significantly affecting complete remission (p = 0.001). TMTV, SDmax, and TP53 status were the main factors of the nomogram and could stratify the patients into four distinct subgroups based on their predicted progression-free survival (PFS). The calibration curve demonstrated satisfactory agreement between the predicted and actual 1-year PFS of the patients. The receiver operating characteristic curves showed this nomogram based on PET/CT metrics and TP53 mutations had a better predictive ability than the clinic risk scores. Similar results were identified upon external validation.

CONCLUSIONS

The nomogram based on imaging factors and TP53 mutations could lead to a more accurate selection of DLBCL patients with rapid progression, to increase tailor therapy.

Radiation and Dose-densification of R-CHOP in Primary Mediastinal B-cell Lymphoma: Subgroup Analysis of the UNFOLDER Trial

UNFOLDER (NCT00278408, EUDRACT 2005-005218-19) is a phase-3 trial in patients with aggressive B-cell lymphoma and intermediate prognosis, including primary mediastinal B-cell lymphoma (PMBCL). In a 2 × 2 factorial design, patients were randomized to 6× R-CHOP-14 or R-CHOP-21 (rituximab, cyclophosphamide, doxorubicin, vincristine, and prediso(lo)ne) and to consolidation radiotherapy to extralymphatic/bulky disease or observation. Response was assessed according to the standardized criteria from 1999, which did not include F-18 fluordesoxyglucose positron emission tomography/computed tomography (FDG-PET) scans. Primary end point was event-free survival (EFS). A subgroup of 131 patients with PMBCLs was included (median age, 34 y; 54% female, 79% elevated lactate dehydrogenase (LDH), 20% LDH >2× upper limit of normal [ULN], and 24% extralymphatic involvement). Eighty-two (R-CHOP-21: 43 and R-CHOP-14: 39) patients were assigned to radiotherapy and 49 (R-CHOP-21: 27, R-CHOP-14: 22) to observation. The 3-year EFS was superior in radiotherapy arm (94% [95% confidence interval (CI), 89-99] versus 78% [95% CI, 66-89]; P = 0.0069), due to a lower rate of partial responses (PRs) (2% versus 10%). PR triggered additional treatment, mostly radiotherapy (n = 5; PR: 4; complete response/unconfirmed complete response: 1). No significant differences were observed in progression-free survival (PFS) (95% [95% CI, 90-100] versus 90% [95% CI, 81-98]; P = 0.25) nor in overall survival (OS) (98% [95% CI, 94-100] versus 96% [95% CI, 90-100]; P = 0.64). Comparing R-CHOP-14 and R-CHOP-21, EFS, PFS, and OS were not different. A prognostic marker for adverse outcome was elevated LDH >2× ULN (EFS: P = 0.016; PFS: P = 0.0049; OS: P = 0.0014). With the limitation of a pre-PET-era trial, the results suggest a benefit of radiotherapy only for patients responding to R-CHOP with PR. PMBCL treated with R-CHOP have a favorable prognosis with a 3-year OS of 97%.

Incidence and risk factors for central nervous system relapse in patients with primary mediastinal large B-cell lymphoma in the rituximab era

Central nervous system (CNS) involvement is rare in primary mediastinal large B-cell lymphoma (PMLBCL). We aimed to evaluate the incidence of CNS relapse as first treatment failure event and the effect of the induction chemotherapy regimen, central nervous system - international prognostic index (CNS-IPI) and other clinical and laboratory variables on the risk of CNS relapse in 564 PMLBCL patients treated with immunochemotherapy. Only 17 patients (3.0%) received CNS prophylaxis. During a 55-month median follow-up only 8 patients experienced CNS relapse as first event, always isolated. The 2-year cumulative incidence of CNS relapse (CI-CNSR) was 1.47% and remained unchanged thereafter. The CI-CNSR was not affected by the chemotherapy regimen (R-CHOP or R-da-EPOCH). None of the established International Prognostic Index factors for aggressive lymphomas predicted CNS relapse in PMLBCL. The 2-year CI-CNSR in patients with versus without kidney involvement was 13.3% versus 0.96% (p < 0.001); 14.3% versus 1.13% with versus without adrenal involvement (p < 0.001); and 10.2% versus 0.97% with versus without either kidney or adrenal involvement. CNS-IPI was also predictive (2-year CI-CNSR in high-risk vs. intermediate/low-risk: 10.37% vs. 0.84%, p < 0.001). However, this association may be driven mainly by kidney and/or adrenal involvement. In conclusion, in PMLBCL, CNS relapse is rare and appears to be strongly associated with kidney and/or adrenal involvement.

High efficacy of intensive immunochemotherapy for primary mediastinal B-cell lymphoma with prolonged follow up

Primary mediastinal B-cell lymphoma (PMBL) is currently curable in 85–95% of patients. Treatment regimens frequently used include RCHOP ± radiotherapy, DAEPOCH-R, or occasionally more intensive protocols. Here we present results of treatment of 124 patients with PMBL over a period between 2004 and 2017 with the use of a protocol designed for aggressive B-cell lymphoma GMALL/B-ALL/NHL2002 including 6 cycles of alternating immunochemotherapy with intermediate-dose methotrexate in each cycle, and reduced total doxorubicin dose (100 mg/m² for whole treatment). Majority of patients (77%) received consolidative radiotherapy. A median (range) age of patients was 30 (18–59) years, and 60% were female. With a median (range) follow up of 9 (1–17) years, 5-year overall survival (OS) and 5-year progression free survival (PFS) were 94% and 92%, respectively. Positron emission tomography—computed tomography (PET-CT) results at the end of chemotherapy were predictive for outcome: OS and PFS at 5 year were 96% and 94% in PET-CT negative patients, respectively, and 70% and 70% in PET-CT-positive patients (p = 0.004 for OS, p = 0.01 for PFS). Eight (6%) patients had recurrent/refractory disease, however, no central nervous system (CNS) relapse was observed. Acute toxicity included pancytopenia grade 3/4, neutropenic fever, and treatment related mortality rate of 0.8%. Second malignancies and late cardiotoxicity occurred in 2.4% and 2.4% of patients, respectively. Intensive alternating immunochemotherapy protocol GMALL/B-ALL/NHL2002 is curative for more than 90% of PMBL patients and late toxicity in young patients is moderated. The attenuated dose of doxorubicin and intermediate dose of methotrexate may contribute to low incidence of late cardiotoxicity and effective CNS prophylaxis.

Less Intensive Regimens May Still Be Suitable for the Initial Treatment of Primary Mediastinal B-Cell Lymphoma in Resource-Limited Settings

Primary mediastinal B-cell lymphoma (PMBCL) is an uncommon disease, consisting of 2–4% of non-Hodgkin lymphomas. Radiotherapy-free DA-EPOCH-R and R-CHOP plus radiotherapy (RT) have been the upfront standard regimens worldwide. However, performing DA-EPOCH-R in resource-constrained settings can be burdensome, especially in low/middle-income countries, where data on PMBCL are still largely unknown. We retrospectively analyzed 93 patients with PMBCL diagnosed between 2008 and 2018 with the intention of comparing the characteristics of the patients and the results obtained with each protocol and to verify if the use of less intensive chemotherapy is still possible to be used. The median age was 28 years, 59.1% were female, 42.3% were in advanced stages, and 92.1% were with bulky disease. DA-EPOCH-R (41.9%), R-CHOP (35.5%), and R-CHOEP (22.6%) were the regimens used, and no difference was observed in the characteristics of the patients. After four cycles of chemotherapy, complete response (CR), partial response (PR), and progressive disease (PD) rates were 40%, 55.7%, and 4.5%, respectively. At the end of treatment, metabolic CR and PD rates were 56.8% and 11.1%. RT was performed in 42.1% of DA-EPOCH-R, 75% of R-CHOP, and 83% of R-CHOEP, and switched PR to CR in 73.7%. Estimated 5-year PFS and OS were 77.2% and 77.4%, respectively. Only LDH levels remained independently associated with PFS, and type of treatment was not associated with OS, PFS, or relapse rate. Therefore, we conclude that in a resource-constrained setting, R-CHOP or R-CHOEP could be still safely adopted in upfront treatment for PMBCL.

Monoclonal Antibodies in the Treatment of Diffuse Large B-Cell Lymphoma: Moving beyond Rituximab

Although rituximab has revolutionized the treatment of diffuse large B-cell lymphoma (DLBCL), a significant proportion of patients experience refractory disease or relapse early after the end of treatment. The lack of effective treatment options in the relapsed/refractory (R/R) setting had made the prognosis of these patients dismal. The initial enthusiasm for novel anti-CD20 antibodies had been short-lived as they failed to prove their superiority to rituximab. Therefore, research has focused on developing novel agents with a unique mechanism of action. Among them, two antibody-drug conjugates, namely polatuzumab vedotin (PolaV) and loncastuximab tesirine, along with tafasitamab, an anti-CD19 bioengineered antibody, have been approved for the treatment of R/R DLBCL. Whereas PolaV has been FDA and EMA approved, EMA has not approved loncastuximab tesirine and tafasitamab yet. Results from randomized trials, as well as real-life data for PolaV have been promising. Novel agents as bispecific antibodies bridging CD3 on T-cells to CD20 have shown very promising results in clinical trials and are expected to gain approval for treatment of R/R DLBCL soon. As the therapeutic armamentarium against DLBCL is expanding, an improvement in survival of patients with R/R and higher cure rates might soon become evident.

Symptomatic ovarian involvement as the initial presentation of primary mediastinal large b-cell lymphoma

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PMLBCL is an uncommon thymic B-cell neoplasm accounting for about 2.5% of NHLs.

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Patients present with bulky mediastinal lymphadenopathy,causing dyspnea and dry cough.

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Extrathoracic distal extranodal sites is a rare event at disease presentation.

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This is a unique case of a young female patient with symptomatic, bulky ovarian tumor.

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PMLBCL was finally diagnosed with a clinically silent bulky mediastinal mass.

Primary mediastinal large B- cell lymphoma (PMLBCL) is a mature aggressive B-cell lymphoma which affects mainly young and middle-aged women. The majority of patients present with bulky mediastinal lymphadenopathy. Extranodal involvement is a rare phenomenon at disease presentation. Herein, we describe a case of a young female with PMLBCL presenting with symptomatic, bulky ovarian involvement. The 23-year old patient presented at the Emergency Department with abdominal pain. The chest X-ray film revealed a mediastinal mass and CT scan revealed a large pelvic mass, possibly involving the ovaries. Due to the development of signs of acute abdomen, she was urgently transferred to the operation room where surgical resection of the right ovary and the adjacent mass was performed. The histological examination of the resected material revealed proliferation of PMLBCL cells. This is the first report in the scientific literature describing symptomatic ovarian mass as the initial mode of presentation of PMLBCL.

Very Early Onset of Therapy-Related Acute Myeloid Leukemia with 11q23 Rearrangement Presenting with Unusual PET Findings after R-DA-EPOCH for Primary Mediastinal Large B-Cell Lymphoma

Background: R-DA-EPOCH is an effective regimen for PMLBCL, which permits the omission of consolidative radiotherapy in the majority of patients. Patient: We describe a 27-year-old female patient, who achieved a complete remission after treatment with six cycles of R-DA-EPOCH (up to the final level). At 6 months after the end of treatment, PET/CT revealed an unexpected, diffusely increased 18FDG uptake by the bone marrow. Simultaneously, pancytopenia with monocytosis was observed. Result: The patient was diagnosed with therapy-related myelodysplastic syndrome, which rapidly evolved into acute myeloid leukemia (t-MDS/AML) with MLL rearrangements. She achieved a complete remission after induction therapy, received an allogenic transplant and remains disease-free 2 years later. Conclusions: The extremely early onset of t-MDS/AML, together with the unexpected PET/CT findings make this case unique and highlights the need for the accurate estimation of the possible dose-dependent risk of t-MDS/AML after R-DA-EPOCH in the real-life setting in patients with PMLBCL.

Current and emerging treatment options in primary mediastinal B-cell lymphoma

Previously considered a subtype of diffuse large B-cell lymphoma (DLBCL), primary mediastinal B-cell lymphoma (PMBCL) is now recognized by the World Health Organization as an independent entity. PMBCL has clinicopathologic features that are separate from systemic DLBCL and harbors some biologic characteristics which overlap with nodular sclerosing classic Hodgkin’s lymphoma (cHL). Similar to cHL, copy number alterations of 9p24.1 are frequently seen in PMBCL, which leads to increased expression of key genes in the region, including programmed death-ligand 1( PD-L1), PD-L2, and JAK2. In addition, PMBCL cells express CD30 in a mostly patchy fashion. In the upfront setting, dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (i.e., DA-EPOCH-R) is the only regimen that has been shown in a prospective setting to result in outstanding outcomes without consolidative radiation to the mediastinum, with a 5-year event-free survival rate of 93% and overall survival rate of 97%. Thus, in recent years, DA-EPOCH-R has been recognized as the preferred frontline regimen. Despite the encouraging results in the frontline setting, the outcomes in the relapsed/refractory setting remain poor. The current approach of salvage chemotherapy followed by autologous stem cell transplantation, as used in patients with DLBCL, does not result in high rates of cure in patients with rrPMBCL. In recent years, the characteristic molecular features identified in PMBCL have provided more treatment opportunities for this patient population. In the relapsed setting, single-agent PD-1 inhibitor pembrolizumab have demonstrated high and durable remission rates. Despite the expression of CD30, the CD30 antibody drug-conjugate brentuximab vedotin (BV) as a single agent has been deemed inactive in this disease. On the contrary, the combinations of BV and PD-1 inhibitor have shown higher response rates than PD-1 inhibitor alone. Moreover, anti-CD19 chimeric antigen receptor T-cell (CAR T-cell) therapy has been positioned as another successful strategy for patients with rrPMBCL. Axicabtagene ciloleucel and lisocabtagene maraleucel are two products used in rrPMBCL.