Treatment Of Malignant Pleural Mesothelioma Research Articles

Aerostasis to limit air leak following extended pleurectomy-decortication.

Extended pleurectomy-decortication is a cytoreductive surgical treatment for malignant pleural mesothelioma. Prolonged air leak remains a major postoperative challenge, lengthening hospital stay and increasing morbidity. In this video report, we present a stepwise approach for visceral decortication and introduce the concept of aerostasis by construction of an artificial neopleura. Our results suggest that improved aerostasis results in shortened air leak duration.

Development of Patient and Caregiver Conceptual Models Investigating the Health-Related Quality of Life Impacts of Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a rare and usually fatal malignancy frequently linked to occupational asbestos exposures and associated with poor prognosis and considerable humanistic burden. The study aimed to develop conceptual models of the health-related quality of life (HRQoL) impact on patients with and receiving treatment for MPM, and the burden on their caregivers. This multi-country study (Australia and United Kingdom) adopted a qualitative methodology to conduct semi-structured, independent interviews with people with MPM (n = 26), current caregivers (n = 20), and caregivers of people who had recently died because of MPM (n = 4). Participants were recruited using a purposive sampling approach and interviews conducted via telephone between January 2021 and January 2022. Transcripts were analysed using thematic analysis and used to construct conceptual models. Patient analysis yielded four overarching themes: (1) debilitating burden of breathlessness and fatigue; (2) physical mesothelioma symptoms experienced by patients; (3) distress of MPM on the self and family; and (4) treatment is worth 'having a go' despite the potential impact on symptoms. Caregiver analysis yielded five core themes: (1) daily life limited by caregiving duties; (2) emotional well-being and the need for support; (3) the relational role shift to caregiver; (4) time spent providing care negatively impacts work and productivity; and (5) positive aspects and outcomes of caregiving. This study highlights the substantial daily and emotional HRQoL impact that MPM symptoms have on patients and caregivers. Both groups reduced work, productivity, and social and leisure activities. There was evidence of positive HRQoL impacts as a result of immunotherapy and radiotherapy, but less for chemotherapy. Caregiver impacts were intensified during the end-of-life period and persisted following patient death. Evident is a need for increased psychological support, information, and advice for caregivers, increased during the end-of-life period.

Abstract 4085: The anti-VISTA x MSLN bispecific antibody-interferon beta mutein fusion protein: A trispecific immunocytokine with potent therapeutic efficacy against malignant pleural mesothelioma

Abstract Background Malignant pleural mesothelioma (MPM) is a rare and highly fatal cancer primarily induced by asbestos exposure. The 5-year overall survival rate for MPM patients is less than 20%. Before the FDA approval of the combination of immune checkpoint inhibitors (Nivolumab + Ipilimumab, CHECKMATE-743), chemotherapy was the only systemic therapy for MPM. However, the predominant histological type of MPM, epithelioid MPM, comprising approximately 70% of cases, showed limited clinical benefits from immune checkpoint inhibitors when compared to non-epithelioid histology. Consequently, there is an unmet medical need to develop a new anti-cancer drug specifically for the treatment of epithelioid MPM. In this study, we discovered that V-domain Ig suppressor of T cell activation (VISTA), an immune checkpoint protein, and Mesothelin (MSLN), a tumor differentiation antigen, are co-expressed in epithelioid MPM. Subsequently, we developed a biomarker-based anti-VISTA x MSLN bispecific antibody (BsAb) and anti-VISTA x MSLN BsAb-IFN-β mutein fusion protein (trispecific immunocytokine) for the treatment of epithelioid MPM. Method We designed and screened various structures of the anti-VISTA x MSLN BsAb. To produce the trispecific immunocytokine, we fused IFN-β mutein (R27T/C17S), which exhibits improved stability, productivity, and pharmacokinetic properties compare to recombinant IFN-β. The in vitro efficacy of the trispecific immunocytokine was tested in human MPM cell lines, and its in vivo efficacy was evaluated in a human MPM xenograft mouse model and a human IFNAR1/2 Knock-in (KI) mouse model. Results We demonstrated a strong positive correlation between the expression levels of VISTA and MSLN in epithelioid MPM. The Anti-VISTA x MSLN BsAb showed improved binding affinity and antibody-dependent cell cytotoxicity (ADCC) activity. The trispecific immunocytokine displays analogous biological activities to both Anti-VISTA x MSLN BsAb and IFN-β mutein. The trispecific immunocytokine exhibited potent in vivo and in vitro anti-cancer activities against epithelioid MPM preclinical models, operating through both direct cytotoxicity and indirect activation of immune cells. Conclusion The trispecific immunocytokine demonstrated robust in vitro and in vivo anti-cancer efficacy in the epithelioid MPM model. Our findings suggest that the trispecific immunocytoine is a promising drug candidate for epithelioid MPM. Citation Format: Hee Geon Park, Hyeon Ju Kim, Myeung Ryun Seo, Ji Eun Park, Tae Won Kim, Jeung Hoo Choi, Jay Park, Kyoung Song, Chan Gyu Lee, Hae Min Jeong, Jun Young Choi, Yeong Jeong Jeon, Yoon La Choi, Sung Youl Hong, Young Kee Shin. The anti-VISTA x MSLN bispecific antibody-interferon beta mutein fusion protein: A trispecific immunocytokine with potent therapeutic efficacy against malignant pleural mesothelioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4085.

Three-dimensional printing of the human lung pleural cavity model for PDT malignant mesothelioma

ObjectiveThe primary aim was to investigate emerging 3D printing and optical acquisition technologies to refine and enhance photodynamic therapy (PDT) dosimetry in the management of malignant pleural mesothelioma (MPM). Materials and methodsA rigorous digital reconstruction of the pleural lung cavity was conducted utilizing 3D printing and optical scanning methodologies. These reconstructions were systematically assessed against CT-derived data to ascertain their accuracy in representing critical anatomic features and post-resection topographical variations. ResultsThe resulting reconstructions excelled in their anatomical precision, proving instrumental translation for precise dosimetry calculations for PDT. Validation against CT data confirmed the utility of these models not only for enhancing therapeutic planning but also as critical tools for educational and calibration purposes. ConclusionThe research outlined a successful protocol for the precise calculation of light distribution within the complex environment of the pleural cavity, marking a substantive advance in the application of PDT for MPM. This work holds significant promise for individualizing patient care, minimizing collateral radiation exposure, and improving the overall efficiency of MPM treatments.

The role of radiotherapy in the treatment of malignant pleural mesothelioma - possibilities and controversy

Malignant pleural mesothelioma (MPM) is a rare malignancy with poor prognosis. In recent years, significant progress has been made in the treatment of this disease, including surgical and radiotherapy techniques, systemic therapy, and immunotherapy. Due to the wide range of clinical presentations, a lack of phase-III randomized trials, and heterogeneity in treatment approach, the treatment of MPM remains challenging regardless of available diagnostic and therapeutic guidelines. The limited possibility to avoid critical healthy organs (particularly lungs), overexposure of which can lead to severe, and even fatal, radiation-induced toxicity, makes high-dose radical radiotherapy very demanding. Thus, the majority of patients in the era of conventional radiotherapy were mostly referred to no more than palliative radiotherapy. Technological development in radiotherapy such as respiratory gating, 4D computed tomography, intensity-modulated radiotherapy, volumetric modulated arc therapy, stereotactic techniques, and proton therapy, made a step forward in treating MPM with this modality. Today, MPM radiotherapy can be considered in various indications, alone or in combination with surgery and systemic treatment. However, many questions remain open, and further investigation is needed especially in dose escalation possibility and lung sparing.

Current State-of-the-Art Therapy for Malignant Pleural Mesothelioma and Future Options Centered on Immunotherapy.

Malignant pleural mesothelioma (MPM) is a locally aggressive disease related to asbestos exposure with a median survival for untreated patients of 4-8 months. The combination of chemotherapy based on platinum and antifolate is the standard treatment, and the addition of bevacizumab adds two months to median survival. Recently, in first-line treatment, immunotherapy combining nivolumab with ipilimumab has been shown to be superior to chemotherapy in the CheckMate-743 study in terms of overall survival (18.1 months), leading to its approval by the FDA and EMA. The positive results of this study represent a new standard of treatment for patients with MPM; however, not all patients will benefit from immunotherapy treatment. In an effort to improve the selection of patient candidates for immunotherapy for different tumors, biomarkers that have been associated with a greater possibility of response to treatment have been described. MPM is a type of tumor with low mutational load and neo-antigens, making it a relatively non-immunogenic tumor for T cells and possibly less susceptible to responding to immunotherapy. Different retrospective studies have shown that PD-L1 expression occurs in 20-40% of patients and is associated with a poor prognosis; however, the predictive value of PD-L1 in response to immunotherapy has not been confirmed. The purpose of this work is to review the state of the art of MPM treatment in the year 2023, focusing on the efficacy results of first-line or subsequent immunotherapy studies on patients with MPM and possible chemo-immunotherapy combination strategies. Additionally, potential biomarkers of response to immunotherapy will be reviewed, such as histology, PD-L1, lymphocyte populations, and TMB.

Role of Durvalumab (Anti-PD-L1) in the Management of Mesothelioma: A Systematic Review of the Current Literature

Introduction Mesothelioma is a rare and rapidly advancing tumor that usually emerges on the mesothelial surfaces of the pleura or peritoneum. Despite being a well-recognized rare disease for decades, the only approved primary treatment protocol has been platinum-based treatments plus pemetrexed, whether or not bevacizumab is administered. Immunotherapy-based immune checkpoint inhibitors demonstrated a promising antitumor efficacy in a variety of cancer types. This is a systematic review of the current role of durvalumab in the management of this condition. Methods A systematic search was carried out through the databases and search engines. Regardless of study design, line of therapy, mode of therapy, or Eastern Cooperative Oncology Group (ECOG) performance status, studies that primarily focused on the outcomes of treating this disease with durvalumab were eligible for inclusion. After the initial and full-text screenings, five studies were reviewed. Results The median age of the total 235 patients was 66.9 years. Males comprised 174 (74.04%) of the cases, with 61 (25.95%) cases being female. The Epithelioid mesothelioma subtype accounted for 194 (82.55%) of the patients. Durvalumab, in combination with pemetrexed cisplatin/carboplatin as therapy, was used in 109 (48.38%) cases. Durvalumab and tremelimumab were used in the treatment of 40 (17.02%) cases, of which 17 (7.23%) had retreatment with both immunotherapies. Among the patients who underwent durvalumab treatment, 69 (29.36% ) of the individuals previously received carboplatin/pemetrexed and cisplatin/pemetrexed. Conclusion Durvalumab can be utilized as an effective alternative for malignant pleural mesothelioma treatment, providing positive results and acceptable safety profiles.

Perioperative discordance in mesothelioma cell type after pleurectomy/decortication-a possible detrimental effect of neoadjuvant chemotherapy due to epithelial to mesenchymal transition?

To evaluate the accuracy of preoperative histological assessment, factors affecting the accuracy and the subsequent effect on postoperative survival after surgical treatment for malignant pleural mesothelioma(MPM). We analysed the perioperative course of patients who underwent surgery for MPM in a single institution over a 5-year period. The primary endopoint was to evaluate the proportion of histological discordance between preoperative assessment and postoperative histology, while the secondary end-point was to evaluate its prognostic effect on postoperative survival after surgical treatment. One-hundred and twenty-nine patients were included in this study. Histological discordance between preoperative assessment and postoperative histology was found in 27 of 129 patients(20.9%):epithelial to biphasic/sarcomatoid(negative discordance) in 24, and biphasic to epithelial(positive discordance) in 3(p-value < 0,001).All 24 patients exhibiting epithelial-to-mesenchymal transition(EMT) had received neoadjuvant chemotherapy(p-value : 0,006).In the 34 patients who underwent upfront surgery, only one case(2.9%) of EMT was identified(p-value : 0,127).EMT was not associated with a less invasive method of biopsy(p-value : 0.058) nor with the volume or maximum diameter of the biopsy(p-value : 0,358 and 0,518, respectively) but it was significantly associated with the receipt of neoadjuvant chemotherapy(p-value : 0,006).At median follow-up of 17 months(IQR : 11.0-28.0),50(39%) patients are still alive. Overall survival was significantly reduced in those patients who received neoadjuvant chemotherapy and exhibited discordance(EMT) compared to those who did not : 11(95% CI : 6.2-15.8)months vs 19(95% CI : 14.2 -23.8) months(p-value < 0,001). In addition, there was no difference in overall survival between those who received neoadjuvant chemotherapy and those who had upfront surgery : 16(95% CI : 2.5-19.5)months vs 30(95% CI : 11.6-48.4)months(p-value : 0,203). The association of neoadjuvant chemotherapy with perioperative histological discordance can be explained by EMT, which lead to worse survival. Therefore, there is an argument for the preferential use of upfront surgery in the treatment of otherwise resectable MPM.

First-line nivolumab plus ipilimumab for unresectable MPM in China: a cost-effectiveness analysis

BackgroundThe regimen of nivolumab plus ipilimumab (NI) has been recommended by the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology-Malignant Pleural Mesothelioma (Version 1.2022) and Chinese Guidelines for the Clinical Diagnosis and Treatment of Malignant Pleural Mesothelioma (2021 edition) as the first-line treatment for Malignant Pleural Mesothelioma (MPM). But whether immunotherapy has a financial advantage over conventional chemotherapy (pemetrexed plus cisplatin/carboplatin, C) is uncertain.MethodsBased on survival and safety data from the CheckMate 743 clinical trial (NCT02899299), a partitioned survival model was constructed using TreeAge Pro2022 software. The model cycle was set to 1 month and the study period was 10 years. The output indicators included total cost, quality-adjusted life year (QALY) and incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were used to assess the robustness of the results, considering only direct medical costs.Results and discussionThe ICER for group NI versus Group C was $375,656/QALY in all randomized patients, $327,943/QALY in patients with epithelioid histology, and $115,495/QALY in patients with non-epithelioid histology. The ICERs of all three different populations all exceeded the willingness-to-pay threshold (three times the per capita gross domestic product of China in 2021). The results of univariate sensitivity analysis showed that the price of pemetrexed and nivolumab had great influence on the analysis results. The results of the probabilistic sensitivity analysis show that the probability of the NI scheme being more economical in all three different populations was 0.What is new and conclusionFrom the perspective of the Chinese healthcare system, in patients with unresectable MPM, NI has no economic advantage over C.

Mesothelin expression remodeled the immune-matrix tumor microenvironment predicting the risk of death in patients with malignant pleural mesothelioma.

The combination of immunobiological agents with immune checkpoint proteins is a promising treatment for malignant pleural mesothelioma (MPM). Mesothelin and anti-PD-L1 antibody-drug conjugates specifically target malignant neoplastic cells, inhibit the migration and invasion of neoplastic cells, and restore the immune landscape. In this study, we confirmed the importance of mesothelin and examined the relationship between mesothelin and the immune landscape of the tumor microenvironment (TME) in two MPM cohorts. The discovery cohort included 82 MPM cases. Tissue microarray slides were generated, and samples were processed for hematoxylin & eosin staining, immunohistochemistry, and immunofluorescence assays. The relationship between mesothelin, biomarkers of histogenesis, histological aggressiveness, PD-L1, immune cells (CD4, CD8, CD20, CD68), and collagen type I and type V fibers was evaluated by quantitative digital analyses. The outcome was the survival time until death from disease recurrence. The exploratory cohort included 87 malignant mesothelioma (MESO) patients from The Cancer Genome Atlas database. Most patients were male (70.7%) with a history of asbestos exposure (53.7%) and with the epithelioid subtype (89%). Surgical resection was performed in 85.4% of patients, and 14.6% received chemotherapy; 59.8% of patients died from disease extension to the mediastinum. Low tumor mesothelin expression was associated with tumor necrosis and nuclear grade 1, whereas high mesothelin expression was significantly associated with the epithelioid histotype and high density of T cells CD8+, macrophages CD68+, and collagen type I fibers. Cox multivariate analysis showed a high risk of death for non-operated patients [hazard ratio (HR), 3.42 (1.15-10.16)] with low tumor mesothelin levels [HR, 2.58 (1.09-6.10)] and high PD-L1 and low infiltration of T cells CD4+ [HR, 3.81 (1.58-9.18)]. In the exploratory cohort, low mesothelin and high COL1A1 and COL5A1 expression were associated with poor overall survival. Tumor mesothelin expression associated with the TME immune landscape predicts the risk of death for patients with MPM and could be a new target for immunotherapy in MPM.

Phase II Study of Hemithoracic Intensity-Modulated Pleural Radiation Therapy (IMPRINT) for Patients with Pleural Metastases from Thymic Malignancies

Pleural metastases are common sites for recurrence and progression in patients with thymic malignancies. The management of pleural metastases typically involves surgical resection with or without neoadjuvant or adjuvant systemic therapy. After surgical resection of pleural metastases, the 5-year progression-free survival (PFS) rate is about 29-45%. While radiation therapy (RT) is standardly used in the management of locally-advanced thymic malignancies, the role of RT in patients with pleural metastases in unclear. Intensity-modulated pleural radiation therapy (IMPRINT) is a RT technique currently being used to treat malignant pleural mesothelioma (MPM) patients with 2 intact lungs at centers that specialize in MPM treatment. This IMPRINT technique can potentially be extrapolated to thymic patients with pleural metastases. Because the risk of toxicity is of greater concern for thymic patients given their overall relatively favorable prognosis, the rate of toxicity, particularly radiation pneumonitis, needs to be established in the thymic patient population. This is a single-arm, single institution Phase II study of hemithoracic IMPRINT for patients with pleural metastases from thymic malignancies. The primary endpoint of this study is grade 3 or higher radiation pneumonitis within 4 months of completing RT. Secondary endpoints include any toxicity, progression-free survival, patterns of failure and overall survival. Patients must have a pathologically confirmed diagnosis of a thymic malignancy with radiologic or pathologic evidence of pleural metastases. Thymoma or thymic carcinoma are allowed. Patients may have de novo stage IVA disease or recurrent disease in the pleura. There must be no evidence of extrathoracic metastatic disease or contralateral pleural/pericardial disease. Surgical resection of the pleural nodules (ex: pleurectomy/decortication, debulking/metastasectomy) are allowed. Extrapleural pneumonectomy is not allowed. Patients are excluded if they have undergone prior thoracic radiation therapy preventing hemithoracic pleural IMRT, whereas prior thymic bed radiation and/or prior pleural SBRT are allowed. RT will be administered to the ipsilateral pleura to 50.4 Gy in 28 fractions. An optional dose-painting boost to gross disease up to 60 Gy while respecting normal tissue constraints is allowed. Patients can be treated with photon or proton therapy. Simulation, contouring and RT planning guidelines have been developed. Patients will be followed per protocol at regular intervals for at least 12 months following RT. The expected accrual is 36 patients over 4 years. Further information can be found on clinicaltrials.gov (NCT05354570). To be determined. To be determined.

Longitudinal monitoring of response to chemotherapy in patients with malignant pleural mesothelioma by biomarkers.

The aim of the study was to longitudinally investigate the serum levels of mesothelin, sestrin1, hyaluronan synthase 2 (HAS2), midkine, and high mobility group box 1 (HMGB1) before and after chemotherapy and at the time of relapse in malignant pleural mesothelioma (MPM) patients treated with chemotherapy and to compare the changes in biomarker levels with radiological treatment outcome. A total of 64 MPM patients treated with chemotherapy were enrolled in the study and longitudinally followed for changes in biomarker levels in response to treatment. Biomarkers evels were measured in serum using a human ELISA kit. Relative and absolute changes in biomarker levels were compared with the best radiological overall response at each time point. Median survival was 20.0 ± 2.4 (15.3-24.7) months in patients with partial and complete response, 17.0 ± 1.0 (15.0-19.0) months in patients with stable disease, and 9.0 ± 1.0 (7.0-11.0) months in patients with progressive disease. A significant decrease in serum levels of mesothelin, midkine, and HMGB1 was observed in patients with radiologically partial and complete responses to chemotherapy (p< 0.001, p= 0.016, and p= 0.039, respectively). In these patients, mesothelin levels decreased by 15%, midkine levels by 7%, and HMGB1 levels by 15%. In addition, HMGB1 serum levels were found to significantly increase by 15% in patients with radiologically progressive responses to chemotherapy compared to pretreatment serum levels (p= 0.035). In patients with partial and complete response to chemotherapy, mesothelin levels increased by 15%, midkine by 12%, and sestrin1 by 8% when the disease recurred (p= 0.004, p= 0.004 and p= 0.044, respectively). Biomarkers may be useful in the longitudinal monitoring of response to treatment in MPM. However, the results of our study should be validated in larger groups with sufficient case numbers from multicenter institutions.

JSI-124 inhibits cell proliferation and tumor growth by inducing autophagy and apoptosis in murine malignant mesothelioma.

Malignant pleural mesothelioma (MPM), mainly caused by asbestos exposure, has a poor prognosis and lacks effective treatment compared with other cancer types. The intracellular transcription factor signal transducer and activator of transcription 3 (STAT3) is overexpressed and hyperactivated in most human cancers. In this study, the role of STAT3 in murine MPM was examined. Inhibition of the Janus kinase 2 (JAK2)/STAT3 pathway with the selective inhibitor JSI-124 has an antitumor effect in murine MPM. Specifically, we demonstrated that JSI-124 inhibits murine MPM cell growth and induces apoptotic and autophagic cell death. Exposure of RN5 and AB12 cells to JSI-124 resulted in apoptosis via the Bcl-2 family of proteins. JSI-124 triggered autophagosome formation, accumulation, and conversion of LC3I to LC3II. Autophagy inhibitors, Chloroquine (CQ) and Bafilomycin A1 (Baf-A1), inhibited autophagy and sensitized RN5 and AB12 cells to JSI-124-induced apoptosis. Our data indicate that JSI-124 is a promising therapeutic agent for MPM treatment.

Induction of metallothionein expression by supplementation of zinc induces resistance against platinum-based treatment in malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive tumor with a dismal prognosis. Currently, multimodality treatment including chemotherapy with cisplatin or carboplatin in combination with pemetrexed offers the best options. Detoxification of heavy metals in the cell by metallothioneins (MT) is associated with early failure to platin-based chemotherapy. The induction of MTs gene expression or its enzyme results in saturation by exposure to metal ions such as zinc or cadmium. Its therapeutically effect is still not analyzed in depth. In our study, we investigated three MPM cell lines and one fibroblast cell line in the course of cisplatin treatment and supplementation of zinc. Cell state analyses via an enzyme-activity based assay were performed. With this, we were able to analyze apoptosis, necrosis and viability of cells. Additionally, we tested treated cells for changes in metallothionein IIA (MT2A) expression by using quantitative realtime polymerase chain reaction. Zinc supplementation induces gene expression of MT2A. Overall, a zinc dose-dependent induction of apoptosis under platin-based treatment could be observed. This effect could be verified in all analyzed cell lines in varying intensity. MT expression is induced by zinc in a dose-dependent manner and inhibits a successful cisplatin therapy. Therefore, heavy metal exposure during cisplatin therapy, e.g., via cigarette smoke, might be an important factor. This should be considered in further therapeutic approaches.

Optimal surgery for resectable malignant pleural mesothelioma in the setting of multimodality treatment.

The surgical treatment of malignant pleural mesothelioma (MPM) involves procedures to achieve macroscopic complete resection, depending on the patient's condition. We reviewed the evolution of surgical approaches for resectable MPM. Since surgery is no more than a single step in the set of processes in multimodality treatment (MMT), we concluded that these procedures should give precedence to lung preservation and minimize resection whenever possible. Postoperative quality of life must be prioritized when the patient can receive appropriate adjuvant therapy.

Chinese expert consensus on the diagnosis and treatment of malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is a malignant tumor originating from the pleura, and its incidence has been increasing in recent years. Due to the insidious onset and strong local invasiveness of MPM, most patients are diagnosed in the late stage and early screening and treatment for high-risk populations are crucial. The treatment of MPM mainly includes surgery, chemotherapy, and radiotherapy. Immunotherapy and electric field therapy have also been applied, leading to further improvements in patient survival. The Mesothelioma Group of the Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) developed a national consensus on the clinical diagnosis and treatment of MPM based on existing clinical research evidence and the opinions of national experts. This consensus aims to promote the homogenization and standardization of MPM diagnosis and treatment in China, covering epidemiology, diagnosis, treatment, and follow-up.

Phase II study of hemithoracic intensity-modulated pleural radiation therapy (IMPRINT) for patients with pleural metastases from thymic malignancies.

TPS8616 Background: Pleural metastases are common sites for recurrence and progression in patients with thymic malignancies. The management of pleural metastases typically involves surgical resection with or without neoadjuvant or adjuvant systemic therapy. After surgical resection of pleural metastases, the 5-year progression-free survival (PFS) rate is about 29-45%. While radiation therapy (RT) is standardly used in the management of locally-advanced thymic malignancies, the role of RT in patients with pleural metastases in unclear. Intensity-modulated pleural radiation therapy (IMPRINT) is a RT technique currently being used to treat malignant pleural mesothelioma (MPM) patients with 2 intact lungs at centers that specialize in MPM treatment. This IMPRINT technique can potentially be extrapolated to thymic patients with pleural metastases. Because the risk of toxicity is of greater concern for thymic patients given their overall relatively favorable prognosis, the rate of toxicity, particularly radiation pneumonitis, needs to be established in the thymic patient population. Methods: This is a single-arm, single institution Phase II study of hemithoracic IMPRINT for patients with pleural metastases from thymic malignancies. The primary endpoint of this study is grade 3 or higher radiation pneumonitis within 4 months of completing RT. Secondary endpoints include any toxicity, progression-free survival, patterns of failure and overall survival. Patients must have a pathologically confirmed diagnosis of a thymic malignancy with radiologic or pathologic evidence of pleural metastases. Thymoma or thymic carcinoma are allowed. Patients may have de novo stage IVA disease or recurrent disease in the pleura. There must be no evidence of extrathoracic metastatic disease or contralateral pleural/pericardial disease. Surgical resection of the pleural nodules (ex: pleurectomy/decortication, debulking/metastasectomy) are allowed. Extrapleural pneumonectomy is not allowed. Patients are excluded if they have undergone prior thoracic radiation therapy preventing hemithoracic pleural IMRT, whereas prior thymic bed radiation and/or prior pleural SBRT are allowed. RT will be administered to the ipsilateral pleura to 50.4 Gy in 28 fractions. An optional dose-painting boost to gross disease up to 60 Gy while respecting normal tissue constraints is allowed. Patients can be treated with photon or proton therapy. Simulation, contouring and RT planning guidelines have been developed. Patients will be followed per protocol at regular intervals for at least 12 months following RT. The expected accrual is 36 patients over 4 years. Further information can be found on clinicaltrials.gov (NCT05354570). Clinical trial information: NCT05354570 .

Success of Checkpoint Blockade Paves the Way for Novel Immune Therapy in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a malignancy associated with asbestos exposure and is typically categorized as an orphan disease. Recent developments in immunotherapy with anti-PD-1 and anti-CTLA-4 antibodies, specifically with agents nivolumab and ipilimumab, have demonstrated an improvement in overall survival over the previous standard chemotherapy leading to their FDA-approval as first-line therapy for unresectable disease. For quite some time, it has been known that these proteins are not the only ones that function as immune checkpoints in human biology, and the hypothesis that MPM is an immunogenic disease has led to an expanding number of studies investigating alternative checkpoint inhibitors and novel immunotherapy for this malignancy. Early trials are also supporting the notion that therapies that target biological molecules on T cells, cancer cells, or that trigger the antitumor activity of other immune cells may represent the future of MPM treatment. Moreover, mesothelin-targeted therapies are thriving in the field, with forthcoming results from multiple trials signaling an improvement in overall survival when combined with other immunotherapy agents. The following manuscript will review the current state of immune therapy for MPM, explore the knowledge gaps in the field, and discuss ongoing novel immunotherapeutic research in early clinical trials.

Comparison of video-assisted pleurectomy/decortication surgery plus hyperthermic intrathoracic chemotherapy with VATS talc pleurodesis for the treatment of malignant pleural mesothelioma: A pilot study

Hyperthermic intrathoracic chemotherapy (HITHOC) adjunct to surgery for Malignant Pleural Mesothelioma (MPM) has no definite role. The primary objective of this pilot-trial was to evaluate the feasibility for future large studies. The study design was a prospective randomized three-centric pilot trial. We recruited patients diagnosed with MPM and prospectively assigned them to two groups: Group A: Video Assisted Thoracic Surgery (VATS) talc pleurodesis or Group B: Video-assisted P/D plus HITHOC. From November-2011 to July-2017 24 males and 3 females, with a median age of 68-years were enrolled (recruitment rate 5 patients/year). Preoperative stage was I-II, and 18 had epithelioid type. 14 patients were in the Group A. Operative mortality was 0. Follow-up ranged 6–80 months. The median overall survival time started to diverge at 20 months, being 19 months (95% CI 12–25) in Group A and 28 months (95% CI 0–56) in Group B. Survival rate for the epithelioid type was 15 months (95% CI 0–34) in Group A and 45 months (95% CI 0–107) in the Group B. These findings suggest that video-assisted P/D plus HITHOC may improve survival time in MPM patients undergoing surgical treatment and support the need for a larger multicenter randomized clinical trial.

PO-1943 A comparison of proton and photon radiotherapy for treatment of malignant pleural mesothelioma

PO-1943 A comparison of proton and photon radiotherapy for treatment of malignant pleural mesothelioma