[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.

Axicabtagene ciloleucel treatment is more effective in primary mediastinal large B-cell lymphomas than in diffuse large B-cell lymphomas: the Italian CART-SIE study.

Axicabtagene ciloleucel showed efficacy for relapsed/refractory large B-cell lymphomas (LBCL), including primary mediastinal B-cell lymphomas (PMBCL); however, only few PMBCLs were reported. Aim was to evaluate efficacy and safety of axicabtagene ciloleucel in patients with PMBCL compared to those with other LBCL, enrolled in the Italian prospective observational CART-SIE study. PMBCLs (n = 70) were younger, with higher percentage of bulky and refractory disease, compared to other LBCLs (n = 190). Median follow-up time for infused patients was 12.17 months (IQR 5.53,22.73). The overall (complete + partial) response rate (ORR,CR + PR) after bridging was 41% for PMBCL and 28% for other LBCL, p = 0.0102. Thirty days ORR was 78% (53/68) with 50% (34) CR in PMBCL, and 75% (141/187) with 53% (100) CR in other LBCL, p = 0.5457. Ninety days ORR was 69% (45/65) with 65% (42) CR in PMBCL, and 54% (87/162) with 47% (76) CR in other LBCL; progressive disease was 21% in PMBCL and 45% in other LBCL, p = 0.0336. Twelve months progression-free survival was 62% (95% CI: 51-75) in PMBCL versus 48% (95% CI: 41-57) in other LBCL, p = 0.0386. Twelve months overall survival was 86% (95% CI: 78-95) in PMBCL versus 71% (95% CI: 64-79) in other LBCL, p = 0.0034. All grade cytokine release syndrome was 88% (228/260); all grade neurotoxicity was 34% (88/260), with 6% of fatal events in PMBCL. Non-relapse mortality was 3%. In conclusion, PMBCLs achieved significantly better response and survival rates than other LBCLs.

Remarkable response to pazopanib plus vivolumab in a patient with pericardial synovial sarcoma carrying a novel genotype BRCA2 c.968dupT: A case report.

Pericardial synovial sarcomas (PSS) have a low incidence rate and are highly invasive with a dismal prognosis. Standard treatment includes surgery, radiotherapy and chemotherapy but with limited response. Here, we report the case of a 15-year-old nonsmoking youngster diagnosed with PSS who developed disease relapsed from surgery after 1 month. Next-generation sequencing (NGS) using baseline tissue was performed, and BRCA2 c.968dupT was detected. Then pazopanib (a multitargeted inhibitor) plus nivolumab (an immune checkpoint inhibitor) was administered, with a partial response and progression-free survival of 14 months. BRCA2 c.968dupT has not previously been reported in PSS and its response to targeted combination immunotherapy are not well characterized. Here, we report the efficacy of pazopanib combined with nivolumab in a PSS patient harboring BRCA2 c.968dupT and also provide the clinical evidence of the utility of NGS in exploring actionable mutations for solid tumor. Combination therapy based on immunotherapy may be a potential treatment choice for PSS harboring BRCA2 mutation.

A massive immature mediastinal teratoma treated with chemotherapy and surgical resection: a case report.

BACKGROUND: Teratoma is a type of germ cell tumor consisting of one or multiple tissues derived from germinal layers. The location and size of the tumor can cause various presentations. Here we report one of the largest ever cases of immature cystic teratoma. CASE PRESENTATION: In this report, we presented a 24-year-old patient with dyspnea, chest pain, nausea, and anorexia. A computed tomography scan revealed a giant, right-sided mass measuring about 190 × 150 × 140 mm. Chemotherapy was initiated for the patient, followed by thoracotomy. Histopathological evaluation revealed the nature of the mass to be an immature mediastinal teratoma. CONCLUSION: the incidence of immature mediastinal teratoma is uncommon, and due to its rarity, the diagnosis needs more profound evaluation studies such as radiological and pathological assessments. Immature teratomas are optimally treated by a combination of chemotherapy and complete resection.

Treatment strategies and survival outcomes of primary mediastinal large B-cell lymphoma.

OBJECTIVES: Primary mediastinal large B-cel l lymphoma (PMBCL) is a rare subtype of B-cell lymphoma that is not yet fully understood. This population-based study aimed to assess the latest survival and treatment strategies for patients with PMBCL. METHODS: The study used the dataset from the Surveillance, Epidemiology, and End Results Program registry to retrospectively analyze adult patients diagnosed with PMBCL between 2001 and 2018. The primary outcome measures included overall survival (OS) and disease-specific survival (DSS). RESULTS: Among the 814 identified cases, the study revealed a 5-year OS rate of 86.7% and a 5-year DSS rate of 88.2% after a median follow-up of 54 months. Cox regression analysis indicated that age over 60 years, pre-2010 diagnosis, non-White ethnicity, advanced stage, and absence of chemotherapy significantly reduced both OS and DSS. It also found that chemotherapy has remained the primary therapeutic protocol for PMBCL over the last 20 years, whereas the utilization of surgery and radiation declined significantly. Patients diagnosed with PMBCL between 2010 and 2018 had a significantly reduced mortality risk (∼50%) compared to those diagnosed between 2001 and 2009. Notably, in the era of rituximab's widespread usage, recipients of radiotherapy exhibited a poorer OS rate than non-recipients. CONCLUSION: Survival outcomes for patients with PMBCL have significantly improved in the current era, possibly due to the evolving treatment paradigm. The value of radiotherapy in PMBCL is still debated and requires further prospective evaluation.

Pembrolizumab in relapsed or refractory primary mediastinal large B-cell lymphoma: final analysis of KEYNOTE-170.

Previous analyses of the phase 2 KEYNOTE-170 (NCT02576990) study demonstrated effective antitumor activity and acceptable safety of pembrolizumab 200 mg given every 3 weeks for up to 35 cycles (∼2 years) in patients with relapsed/refractory (R/R) primary mediastinal B-cell lymphoma (PMBCL) whose disease progressed after or who were ineligible for autologous stem cell transplantation. The end points included objective response rate (ORR), progression-free survival (PFS), and duration of response (DOR) according to the investigator per 2007 Response Criteria; overall survival (OS); and safety. In this final analysis, median duration of follow-up was 48.7 months (range, 41.2-56.2). The ORR was 41.5% (complete response, 20.8%; partial response, 20.8%). The median DOR was not reached; no patients who achieved a complete response progressed at the data cutoff. The median PFS was 4.3 months; the 4-year PFS rate was 33.0%. The median OS was 22.3 months; the 4-year OS rate was 45.3%. At the data cutoff, 30 patients (56.6%) had any-grade treatment-related adverse events (AEs); the most common were neutropenia, asthenia, and hypothyroidism. Grade 3/4 treatment-related AEs occurred in 22.6% of the patients; no grade 5 AEs occurred. After 4 years of follow-up, pembrolizumab continued to provide durable responses, with promising trends for long-term survival and acceptable safety in R/R PMBCL.

Primary mediastinal/thymic diffuse large B-cell lymphoma: a population-based study on incidence and survival.

Primary mediastinal large B-cell lymphoma is a rare subtype of lymphoma. The contemporary incidence of primary mediastinal large B-cell lymphoma remains unknown, and a large population-based study has not been reported. It is essential to provide guidance for further strategies in reducing the disease burden via population-based preventive initiatives. This study aims to explore the epidemiology and effect of therapeutic advances on the survival of patients with primary mediastinal large B-cell lymphoma. This population-based study was conducted using the Surveillance, Epidemiology, and End Results Program (SEER), covering the period from 1975 to 2018. A total of 774 patients in the SEER 9 and 1654 patients in the SEER 18 were analyzed. The age-adjusted incidence rate of primary mediastinal large B-cell lymphoma increased from 0.05/1,000,000 in 1975 to 2.38/1,000,000 in 2018. A significant positive linear increase in the incidence trend was found in primary mediastinal large B-cell lymphoma, with an annual percent change of 8.47% (95% confidence interval 7.7-9.2%, P < 0.001, z test). The survival in primary mediastinal large B-cell lymphoma was significantly superior to nodal diffuse large B-cell lymphoma. The incidence of PMBCL increases over the year. The survival of patients with primary mediastinal large B-cell lymphoma has improved over time.

Primary Mediastinal B-Cell Lymphoma in Children and Young Adults.

Primary mediastinal B-cell lymphoma (PMBCL) is a rare but aggressive mature B-cell lymphoma that arises from thymic B cells and most commonly affects adolescents and young adults. PMBCL is now recognized by the WHO as a distinct entity from diffuse large B-cell lymphoma (DLBCL), not otherwise specified, with a unique clinical presentation and distinct morphologic features and molecular alterations. Similar to classic Hodgkin lymphoma, PMBCL tumors are characterized by alterations in the nuclear factor-κB and JAK/STAT pathways. These tumors also exhibit an immune evasion phenotype marked by upregulation of PD-L1 and loss of B2M. Historic data indicates that outcomes for pediatric patients with PMBCL are inferior compared with pediatric patients with DLBCL treated on the same protocols, and there is no current standard approach to initial treatment. Common regimens used for children with PMBCL include multiagent chemotherapy regimens designed for Burkitt lymphoma, such as Lymphomes Malins B (LMB)-based or Berlin-Frankfurt-Münster (BFM)-based chemotherapy ± rituximab. Based on initial data in adults showing excellent outcomes with the use of DA-EPOCH-R regimens, these regimens have also been adopted in pediatrics, although with mixed results. Novel agents are currently being studied in PMBCL with the goal of improving outcomes and reducing reliance on radiation and/or high-dose chemotherapy. Immune checkpoint blockade with PD-1 inhibition is of particular interest given the upregulation of PD-L1 in PMBCL and the known efficacy of these agents in the relapsed setting. Future efforts in PMBCL will also seek to determine the role of FDG-PET in evaluating response to therapy and the role of biomarkers in risk stratification.

Morphologic Changes in the Thymus Following Chemotherapy for Anterior Mediastinal Germ Cell Tumors: A Study of 91 Cases Emphasizing Pseudoneoplastic Features.

CONTEXT.­: The interpretation of postchemotherapy resections of anterior mediastinal germ cell tumors plays a critical role in determining future patient management and prognosis. Treatment-related changes in the thymus may mimic residual teratoma or microcystic-pattern yolk sac tumor. There is limited extant information concerning therapy-related pseudoneoplastic thymic alterations. OBJECTIVE.­: To provide diagnostic assistance to distinguish nonneoplastic thymic abnormalities secondary to chemotherapy from residual germ cell tumor. DESIGN.­: We retrospectively reviewed 91 resections of primary anterior mediastinal germ cell tumors with recognizable thymic gland following cisplatin-based chemotherapy. RESULTS.­: The cohort included 90 men and 1 woman (median age, 29 years). A spectrum of thymic epithelial alterations occurred, including cystic change (macrocysts [n = 21] or microcysts [n = 20]); hyperplasia with reactive atypia (n = 8); ciliated, mucinous, or columnar cell metaplasia (n = 3); and mature squamous metaplasia (n = 2). These changes were similar to so-called acquired multilocular thymic cysts, were often contiguous with and adjacent to normal thymic epithelium, and lacked the neoplastic-type atypia seen in teratomatous elements in this setting. In 1 case, confluent microcysts closely mimicked the appearance of yolk sac tumor but lacked other distinctive features of that neoplasm and its characteristic immunoreactivity. CONCLUSIONS.­: Recognition of therapy-induced thymic changes is important to avoid misinterpretation as residual teratoma or yolk sac tumor. Continuity with and proximity to benign thymic epithelium, absence of neoplastic-type atypia, and awareness of this phenomenon are important in avoiding this pitfall.

Resection of a Large Growing Mediastinal Germ Cell Tumor Using a Multidisciplinary Approach.

Mediastinal germ cell tumors (GCTs) are rare. Post-chemotherapy residual masses in patients with a nonseminomatous GCT require resection. A patient with a large mediastinal GCT involving the left subclavian artery, superior vena cava (SVC) and hilum of the right lung is presented. Despite a biochemical response to chemotherapy, the tumor enlarged on serial imaging. With guidance from medical oncology, a multidisciplinary surgical team, including cardiac anesthesia, cardiac surgery and thoracic surgery resected the tumor with a staged reconstruction of the SVC. The procedure was well tolerated and yielded clear margins. The final pathology showed a significant associated component of rhabdomyosarcoma.

Primary mediastinal seminoma with leiomyosarcoma: a rare case report.

Germ cell tumor is the most common malignant tumor of the gonads, sometimes they are found in locations other than the gonads, called Extra-gonadal Germ cell tumours (EGCTs). Primary mediastinal germ cell tumors (PMGCTs) are a kind of rare neoplasm in the anterior mediastinum, including seminoma and non-seminomatous, or appear as a mixture. Primary mediastinal seminoma mixed with sarcoma is an extremely rare clinicopathologic entity. Previous studies have revealed that primary pure mediastinal seminomas are commonly sensitive to chemoradiotherapy and possibly to palliative excision. The treatment options for mixed germ cell tumor composed of seminoma and sarcoma remain unknown. Only one case of primary mediastinal seminoma with rhabdosarcoma has been reported in the literature up to date and the patient benefited from chemotherapy as the neoadjuvant therapy. However, cases of primary mediastinal seminoma with leiomyosarcoma have not been documented. Herein, we report a case of an 18-year-old patient, who presented with dyspnea, orthopnea, and chest pain, the CECT scan of the chest showed a large mass in the anterior mediastinum, which turned out to be seminoma mixed with leiomyosarcoma after partial excision. We investigate the treatment strategy and potential molecular mechanism of this disease. Finally, our study demonstrated that the patient benefited from the treatment of chemotherapy alone, or combined with target therapy after the operation. Meanwhile, the BRAF p.G466V, TP53 mutations, MTOR p.T1977I and exons 2-5 deletion of FLCN may be potential molecular mechanisms and oncogenic drivers of this disease.

How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.

PURPOSE: To present the current evidence and the development of studies in recent years on the management of extragonadal germ cell tumors (EGCT). METHODS: A systematic literature search was conducted in Medline and the Cochrane Library. Studies within the search period (January 2010 to February 2021) that addressed the classification, diagnosis, prognosis, treatment, and follow-up of extragonadal tumors were included. Risk of bias was assessed and relevant data were extracted in evidence tables. RESULTS: The systematic search identified nine studies. Germ cell tumors (GCT) arise predominantly from within the testis, but about 5% of the tumors are primarily located extragonadal. EGCT are localized primarily mediastinal or retroperitoneal in the midline of the body. EGCT patients are classified according to the IGCCCG classification. Consecutively, all mediastinal non-seminomatous EGCT patients belong to the "poor prognosis" group. In contrast mediastinal seminoma and both retroperitoneal seminoma and non-seminoma patients seem to have a similar prognosis as patients with gonadal GCTs and metastasis at theses respective sites. The standard chemotherapy regimen for patients with a EGCT consists of 3-4 cycles (good vs intermediate prognosis) of bleomycin, etoposid, cisplatin (BEP); however, due to their very poor prognosis patients with non-seminomatous mediastinal GCT should receive a dose-intensified or high-dose chemotherapy approach upfront on an individual basis and should thus be referred to expert centers Ifosfamide may be exchanged for bleomycin in cases of additional pulmonary metastasis due to subsequently planned resections. In general patients with non-seminomatous EGCT, residual tumor resection (RTR) should be performed after chemotherapy. CONCLUSION: In general, non-seminomatous EGCT have a poorer prognosis compared to testicular GCT, while seminomatous EGGCT seem to have a similar prognosis to patients with metastatic testicular seminoma. The current insights on EGCT are limited, since all data are mainly based on case series and studies with small patient numbers and non-comparative studies. In general, systemic treatment should be performed like in testicular metastatic GCTs but upfront dose intensification of chemotherapy should be considered for mediastinal non-seminoma patients. Thus, EGCT should be referred to interdisciplinary centers with utmost experience in the treatment of germ cell tumors.

Primary non-gestational mediastinal choriocarcinoma metastatic to the brainstem.

Choriocarcinoma is a highly malignant tumour emerging from the syncytiotrophoblast divided into gestational and non-gestational presentations. Primary choriocarcinoma of the mediastinum is rare. Metastases to the brain often occur; however, brainstem involvement has not been reported for non-gestational choriocarcinoma. We described a middle-aged man who developed a complete left oculomotor nerve paralysis secondary to a brainstem tumour at the midbrain. The workup for the primary source of the brainstem tumour included a chest CT scan, which revealed a mediastinal mass. A mediastinal mass needle biopsy confirmed the diagnosis of primary mediastinal choriocarcinoma. Despite aggressive chemotherapy, the patient died 6 months after the initial presentation from neurological complications and multiorgan failure.

End of treatment FDG-PET in primary mediastinal B-cell lymphoma treated with R-chemotherapy: Prognostic indicator and implications for consolidation radiotherapy.

The ideal therapeutic regimen in primary mediastinal B-cell lymphoma (PMBCL) is controversial and may include consolidation radiotherapy (RT). An adequate strategy is essential in a population where long-term effects of RT are significant. We evaluated the prognostic value of end-of-treatment (EOT) FDG-PET in 50 patients receiving rituximab and anthracycline-containing chemotherapy and its implications for consolidative RT. Thirty patients (60%) obtained complete metabolic response (CMR), five received consolidation RT. The remaining patients had partial response (14) and progression (6). Of these, 12 received mediastinal RT, six salvage chemotherapy, and two no further treatment. Five-year progression free survival was 100% and 48% (95% CI 30%-77%) in patients with negative and positive EOT FDG-PET, respectively (P < .001). Five-year overall survival for negative and positive EOT FDG-PET was 100% and 67% (95% CI 48%-93%) respectively (P = .001). Within positive EOT FDG-PET cases, an association was found between Deauville score and survival. The negative predictive value (NPV) of EOT FDG-PET for disease relapse/progression was 100% (95% CI 0.88-1.00); the positive predictive value was 47% (95% CI 0.24-0.71). This study demonstrates the importance of metabolic assessment in PMBCL and is relevant for its high NPV. Our data favor the use of EOT FDG-PET for decisions concerning RT.

Dose-adjusted EPOCH-R is not superior to sequential R-CHOP/R-ICE as a frontline treatment for newly diagnosed primary mediastinal B-cell lymphoma: Results of a bi-center retrospective study.

PURPOSE: Primary mediastinal B-cell lymphoma (PMBCL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL). Despite its aggressive course, PMBCL is considered curable. While in recent years dose-adjusted (DA) EPOCH-R (rituximab, etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) has become widely endorsed as first-line therapy for newly-diagnosed PMBCL, the optimal treatment for this disease and the role of radiotherapy (RT) remains unclear. DA-EPOCH-R provides good clinical outcomes, albeit is associated with short- and long-term toxicity. To address this issue, the current retrospective bi-icenter analysis compared efficacy and toxicity of DA-EPOCH-R and a less toxic R-CHOP/R-ICE regimen used for the treatment of newly-diagnosed PMBCL. PATIENTS AND METHODS: The study included all patients with a histologically confirmed PMBCL diagnosis treated with DA-EPOCH-R or R-CHOP/R-ICE between 01/2013-12/2020 at two tertiary medical centers. Patient demographic and clinical data were derived from institutional electronic medical records. The analysis included 56 patients: 31 received DA-EPOCH-R and 25 - R-CHOP/R-ICE. RESULTS: At a median follow-up of 1.9 years (IQR 3.1 years), similar progression-free survival (2.1 versus 2.4 years; p = 0.7667), overall survival (2.5 versus 2.7 years; p = 0.8047) and complete response (80%) were observed in both groups. However, DA-EPOCH-R was associated with significantly longer hospitalization required for its administration (p < 0.001) and a trend for higher frequency of infections, stomatitis, thrombotic complications and febrile neutropenia-related hospitalizations. CONCLUSION: DA-EPOCH-R and R-CHOP/R-ICE provide similarly encouraging outcomes in newly-diagnosed PMBCL patients. R-CHOP/R-ICE is associated with lower toxicity and significantly reduced hospitalization. Our findings suggest that this regimen may be considered as an alternative to DA-EPOCH-R in this patient population.

The Role of TP53 in Cisplatin Resistance in Mediastinal and Testicular Germ Cell Tumors.

Germ cell tumors (GCTs) are considered to be highly curable; however, there are major differences in the outcomes related to histology and anatomical localization. GCTs originating from the testis are, overall, sensitive to platinum-based chemotherapy, whereas GCTs originating from the mediastinum show a worse response, which remains largely unexplained. Here, we address the differences among GCTs from two different anatomical locations (testicular versus mediastinal/extragonadal), with a specific focus on the role of the P53 pathway. It was recently shown that GCTs with TP53 mutations most often localize to the mediastinum. To elucidate the underlying mechanism, TP53 knock-out lines were generated in cisplatin-sensitive and -resistant clones of the representative 2102Ep cell line (wild-type TP53 testicular GCT) and NCCIT cell line (hemizygously mutated TP53, mutant TP53 mediastinal GCT). The full knock-out of TP53 in 2102Ep and resistant NCCIT resulted in an increase in cisplatin resistance, suggesting a contributing role for P53, even in NCCIT, in which P53 had been reported to be non-functional. In conclusion, these results suggest that TP53 mutations contribute to the cisplatin-resistant phenotype of mediastinal GCTs and, therefore, are a potential candidate for targeted treatment. This knowledge provides a novel model system to elucidate the underlying mechanism of clinical behavior and possible alternative treatment of the TP53 mutant and mediastinal GCTs.