Current surgical strategies for malignant pleural mesothelioma

Prognostic value of 18F-FDG PET/CT in malignant pleural mesothelioma: a meta-analysis

BACKGROUND

Several FDG PET/CT parameters have been utilized to evaluate the prognosis in malignant pleural mesothelioma (MPM). However, there are still controversial results due to the low incidence of MPM.

PURPOSE

To assess the prognostic value of 18F-FDG PET/CT in MPM.

MATERIAL AND METHODS

A systematic literature search was performed in PubMed, Embase, Medline, and The Cochrane Library to identify eligible studies from inception to 12 February 2020. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) of several variables, such as maximum standardized uptake value (SUV_max), the reduction of SUV_max after treatment (ΔSUV_max), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and the reduction of TLG after treatment (ΔTLG), were calculated. Meta-regression with subsequent subgroup analyses were conducted to determine the heterogeneity of cutoff values, treatment regimen, study design, uptake time, and scanners across various studies.

RESULTS

In total, 19 eligible studies including 1819 patients were enrolled in the meta-analysis. The univariate analysis showed that the pooled HRs (95% CI) of SUV_max, ΔSUV_max, MTV, TLG, and ΔTLG were 1.29 (1.16-1.42), 1.12 (1.05-1.19), 1.15 (1.00-1.33), 1.47 (1.23-1.76), and 1.27 (1.12-1.45), respectively. The multivariate analysis showed that the pooled HRs (95% CI) of SUV_max, ΔSUV_max, MTV, and TLG for overall survival (OS) were 1.20 (1.08-1.33), 1.10 (1.02-1.19), 0.95 (0.81-1.11), and 1.13 (1.08-1.18), respectively.

CONCLUSION

SUV_max, ΔSUV_max, TLG, and ΔTLG are significant prognostic indicators for OS, while more clinical studies are needed to confirm the prognostic value of MTV in MPM.

Incidence and Risk Factors of Chest Wall Metastasis at Biopsy Sites in Patients with Malignant Pleural Mesothelioma

To investigate the incidence and risk factors of chest wall metastasis (CWM) at biopsy sites in patients with malignant pleural mesothelioma (MPM). This retrospective cohort study was conducted in 262 consecutive MPM patients who underwent multimodal treatment in which including neoadjuvant chemotherapy (NAC) and curative-intent surgery, from August 2009 to March 2021. CWM was evaluated radiologically (r-CWM) and pathologically (p-CWM). We also investigated the risk factors of p-CWM and the consistency between r-CWM and p-CWM. Of 262 patients, 25 patients were excluded from analysis due to missing data or impossibility of evaluation. Of the eligible 237 patients, pleural biopsy was performed via video-assisted thoracoscopic surgery in 197 (83.1%) and medical thoracoscopy in 40 (16.9%). Pleurodesis was performed after pleural biopsy in 74 patients (31.2%). All patients received NAC followed by curative-intent surgery. Radiological examination showed r-CWM in 43 patients (18.1%), while pathological examination showed p-CWM in 135 patients (57.0%). The incidence of p-CWM was significantly higher in the patients who received pleurodesis after pleural biopsy (77.0% vs. 47.9%, <0.001). Multivariate logistic regression analysis for p-CWM revealed that pleurodesis is an independent risk factor of p-CWM (adjusted hazard ratio, 3.46; 95% confidence interval, 1.84−6.52, <0.001). CWM at the biopsy site was pathologically proven in more than half of the patients (57.0%) who received NAC followed by curative-intent surgery, which was higher than the numbers diagnosed by radiological examinations (p-CWM: 57.0% vs. r-CWM: 18.1%). Pleurodesis after pleural biopsy is an independent risk factor of p-CWM.

CUL4B is a Potential Novel Prognostic Biomarker and is Correlated with Immune Infiltrates in Malignant Pleural Mesothelioma

Background

Methods

Results

Conclusion

Japanese Current Status of Curative-Intent Surgery for Malignant Pleural Mesothelioma

BACKGROUND

Few reports about surgical outcomes in malignant pleural mesothelioma (MPM) were based on reliable nationwide databases. Here we analyzed the incidence, surgical outcome, and operative risk factors using Japanese nationwide database.

METHODS

Characteristics and perioperative data from 622 patients who underwent curative-intent surgery for MPM between January 2014 and December 2017 were recorded from National Clinical Database of Japan. We analyzed the incidence, surgical outcomes, and risk factors for surgical complications after two surgical procedures (extrapleural pneumonectomy, EPP; and pleurectomy/decortication, P/D).

RESULTS

During 4 years, EPP was performed in 279 patients and P/D in 343. EPP was more frequently performed in less-MPM-experienced institutions, while P/D was more frequently performed in well-MPM-experienced institutions (P < .001), especially in high-volume centers with more than 10 cases during this period. P/D was more frequently performed, especially in high-volume centers. The morbidity rates were 45.2% in EPP and 35.9% in P/D. Heart failure and pneumonia were most frequent in EPP, while prolonged air leakage was most frequent in P/D. Thirty-day- and in-hospital mortality rates were 1.1% and 3.2% (EPP) and 1.2% and 3.2% (P/D), respectively. Regression analyses revealed that higher age (>65 years) was associated with operative complications in EPP (odds ratio, OR: 3.56 [1.26-8.56]), whereas no risk factor was observed in P/D.

CONCLUSIONS

In Japanese nationwide annual database, P/D was more frequently performed, especially in high-volume centers. Morbidity was higher in EPP than P/D; however, the mortality rates were quite low in Japan regardless surgical procedures.

Establishment and Characterization of Patient-Derived Xenografts (PDXs) of Different Histology from Malignant Pleural Mesothelioma Patients

Simple Summary

Malignant pleural mesothelioma (MPM) is a rare tumor with unfavorable prognosis for which new therapeutic interventions are urgently needed. The aim of our study was to develop a preclinical model representative of the different histotypes found in human tumors that can be used as models for the discovery of new treatments and combinations. We successfully generated patient-derived xenografts (PDXs) from MPM, which strongly resembled the tumors of origin in terms of morphology and immunohistochemistry. These tumors, when growing in mice, poorly respond to cisplatin, a finding that aligned with the clinical results. From one of the PDXs, we generated 2D and 3D cultures maintaining the phenotypical characteristics of human tumors and PDXs. Altogether, these preclinical models represent a useful tool for the discovery of new targets and drug combinations.

Abstract

Background: Malignant pleural mesothelioma (MPM) is a very aggressive tumor originating from mesothelial cells. Although several etiological factors were reported to contribute to MPM onset, environmental exposure to asbestos is certainly a major risk factor. The latency between asbestos (or asbestos-like fibers) exposure and MPM onset is very long. MPM continues to be a tumor with poor prognosis despite the introduction of new therapies including immunotherapy. One of the major problems is the low number of preclinical models able to recapitulate the features of human tumors. This impacts the possible discovery of new treatments and combinations. Methods: In this work, we aimed to generate patient-derived xenografts (PDXs) from MPM patients covering the three major histotypes (epithelioid, sarcomatoid, and mixed) occurring in the clinic. To do this, we obtained fresh tumors from biopsies or pleurectomies, and samples were subcutaneously implanted in immunodeficient mice within 24 h. Results: We successfully isolated different PDXs and particularly concentrated our efforts on three covering the three histotypes. The tumors that grew in mice compared well histologically with the tumors of origin, and showed stable growth in mice and a low response to cisplatin, as was observed in the clinic. Conclusions: These models are helpful in testing new drugs and combinations that, if successful, could rapidly translate to the clinical setting.

SMO mutations confer poor prognosis in malignant pleural mesothelioma

Background

Malignant pleural mesothelioma (MPM) is an aggressive tumor but approximately 12% of patients survive more than 3 years. The biological differences underlying better outcomes are not known. Several targeted agents and immunotherapy have been ineffective. Hedgehog (Hh) is one emerging pathway. We compared the biological profiles of patients with different survival, investigating the most frequently altered genes, including the Hh pathway.

Methods

We analyzed 56 MPM. A 36-month overall survival (OS) cut-off divided patients into 32 normo (NS) and 24 long (LS) survivors. We used next generation sequencing to test 21 genes, immunohistochemistry to evaluate SMO expression. Mutation differences between NS and LS and their associations with clinical features were analysed by Fisher’s test, OS with the Kaplan-Meier method and its association with mutations by univariate and multivariate Cox proportional hazard models.

Results

Clinical features were similar in both groups. Eighteen out of 56 patients (32%) were wild-type for the genes analysed. At least five had mutations in BAP1, NF2, TP53, SMO and PTCH1 with no significant differences between the groups except for SMO. SMO, a member of the Hh pathway, was mutated only in NS (15.6%) and only SMO mutations were significantly associated with poor prognosis at univariate (HR =4.36, 95% CI: 2.32–8.18, P<0.0001) and multivariate (HR =9.2, 95% CI: 3.0–28.4, P=0.0001) analysis. All SMO mutated patients expressed high protein levels.

Conclusions

SMO mutations were clearly associated with worse prognosis. SMO may be a therapeutic target but this needs to be confirmed in a prospective trial.

Genomics and Functional Genomics of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer of the mesothelial cells lining the pleural surface of the chest wall and lung. The etiology of MPM is strongly associated with prior exposure to asbestos fibers, and the median survival rate of the diagnosed patients is approximately one year. Despite the latest advancements in surgical techniques and systemic therapies, currently available treatment modalities of MPM fail to provide long-term survival. The increasing incidence of MPM highlights the need for finding effective treatments. Targeted therapies offer personalized treatments in many cancers. However, targeted therapy in MPM is not recommended by clinical guidelines mainly because of poor target definition. A better understanding of the molecular and cellular mechanisms and the predictors of poor clinical outcomes of MPM is required to identify novel targets and develop precise and effective treatments. Recent advances in the genomics and functional genomics fields have provided groundbreaking insights into the genomic and molecular profiles of MPM and enabled the functional characterization of the genetic alterations. This review provides a comprehensive overview of the relevant literature and highlights the potential of state-of-the-art genomics and functional genomics research to facilitate the development of novel diagnostics and therapeutic modalities in MPM.

Clinical feature of diagnostic challenging cases for pleural biopsy in patient with malignant pleural mesothelioma

OBJECTIVE

Pleural biopsy through video-assisted thoracic surgery (VATS pleural biopsy) is the most reliable diagnostic procedure for malignant pleural mesothelioma (MPM). However, definitive diagnosis of MPM is occasionally difficult to establish. This study aims to investigate clinicopathological features of MPM patients who failed diagnosis by the first VATS pleural biopsy.

METHODS

Four hundred consecutive patients with suspected MPM who received VATS pleural biopsy between March 2004 and July 2017 were enrolled in this retrospective study. Patients, whose histological diagnoses were not definitive in the first VATS pleural biopsy, were followed up as atypical mesothelial proliferation (AMP) or non-specific pleuritis (NSP). Re-examination was performed in cases strongly suspected of having MPM.

RESULTS

Of the 400 patients, 267 (66.8%) were pathologically diagnosed with MPM, 25 with metastatic carcinoma and 6 with benign pleural disease by the first VATS pleural biopsy. Of the remaining 102 patients diagnosed with AMP or NSP, 10 patients (9.8%) were subsequently diagnosed with MPM. Analysis of the clinical course revealed that only insufficient tissue for diagnosis was obtained via VATS pleural biopsy in all cases and that it was caused by very early stage without visible tumour in 4 patients, intrathoracic inflammation in 4 and desmoplastic MPM in 2.

CONCLUSIONS

In our review, 9.8% of patients diagnosed with AMP or NSP in first VATS pleural biopsy were subsequently diagnosed with MPM due to insufficient tissue for diagnosis. Definitive diagnosis via VATS pleural biopsy is sometimes challenging in following situation; very early stage, intrathoracic inflammation and desmoplastic MPM.

Tumor Growth Assessment by Computed Tomography Perfusion Imaging (CTPI), Perfusion-Weighted Imaging (PWI), and Diffusion-Weighted Imaging (DWI) in a Rabbit Pleural Squamous Cell Carcinoma VX2-Implanted Model

Background

Computed tomography perfusion imaging (CTPI) and perfusion-weighted imaging (PWI) are non-invasive technologies that can quantify tumor vascularity and blood flow. This study explored the blood flow information, tumor cell viability, and hydrothoraces in a rabbit pleural VX2-implanted model through use of CTPI, PWI, and DWI.

Material/Methods

A pleural VX2-implanted model was established in 58 New Zealand white rabbits. CTPI, PWI, and DWI were applied with a 16-slice spiral CT and an Archival 1.5 T dual-gradient MRI.

Results

Compared with muscle tissue, PV, PEI, and BV of parietal and visceral pleural tumor implantation rabbits showed significant differences. The t values of PV, PEI, and BV between parietal and visceral pleura were 2.08, 2.29, and 2.88, respectively. Compared with muscle tissue, WIR, WOR, and MAXR of parietal and visceral pleural tumor implantation rabbits showed significant differences. In parietal pleural tumor implantation rabbits, the section surface of lesion tissues was 5.2±2.7 cm². Hydrothorax appeared 6.0±2.0 days after tumor implantation. The mean value of ADC was 1.5±0.6. In visceral pleural tumor implantation rabbits, the section surface of lesion tissues was 1.6±0.8 cm². Hydrothorax appeared 7.0±3.0 days after tumor implantation. The mean value of ADC was 1.4±0.5. The t values of the above 3 indices for the parietal and visceral pleura were 1.85, 1.83, and 1.76, respectively (P<0.05).

Conclusions

The combined application of CTPI, PWI, and DWI accurately and visually reflects the blood perfusion of tumor tissues and quantitatively analyzes blood flow information and the mechanism underlying hydrothorax generation in tumor tissues.

Is Pleurectomy/Decortication Superior to Extrapleural Pneumonectomy for Patients with Malignant Pleural Mesothelioma? A Single-Institutional Experience

PURPOSE

This study was performed to compare the outcome of pleurectomy/decortication (P/D) with that of extrapleural pneumonectomy (EPP) for patients with malignant pleural mesothelioma (MPM).

METHODS

Patients with MPM underwent either P/D or EPP from August 2008 to December 2014. Various clinicopathological factors were analyzed to identify differences between the two procedures.

RESULTS

P/D was performed in nine patients and EPP in 30 patients. Most of the patients' background characteristics were not significantly different between the groups. The surgery time (680 vs. 586 min, p = 0.0034) and bleeding volume (4050 vs. 2110 mL, p = 0.002) were significantly greater in P/D than in EPP; however, grade ≥3 complications (44% vs. 33%, p = 0.54) and length of postoperative hospital stay (29 vs. 37 days, p = 0.26) were not significantly different. The median survival time and 2- and 3-year survival rates in all patients were 16.7 months, 28.5%, and 15.3%, respectively. The median survival time and 2- and 3-year survival in the P/D and EPP groups were 22.5 months, 43.8%, and 43.8% and 16.5 months, 24.0%, and 14.4%, respectively (p = 0.13).

CONCLUSION

Survival of patients with MPM remains poor despite multidisciplinary treatment. P/D is comparable with EPP and could be a safe and another surgical treatment for patients with MPM.

Targeting the Hippo Pathway Is a New Potential Therapeutic Modality for Malignant Mesothelioma

Malignant mesothelioma (MM) constitutes a very aggressive tumor that arises from the pleural or peritoneal cavities and is highly refractory to conventional therapies. Several key genetic alterations are associated with the development and progression of MM including mutations of the CDKN2A/ARF, NF2, and BAP1 tumor-suppressor genes. Notably, activating oncogene mutations are very rare; thus, it is difficult to develop effective inhibitors to treat MM. The NF2 gene encodes merlin, a protein that regulates multiple cell-signaling cascades including the Hippo pathway. MMs also exhibit inactivation of Hippo pathway components including LATS1/2, strongly suggesting that merlin-Hippo pathway dysregulation plays a key role in the development and progression of MM. Furthermore, Hippo pathway inactivation has been shown to result in constitutive activation of the YAP1/TAZ transcriptional coactivators, thereby conferring malignant phenotypes to mesothelial cells. Critical YAP1/TAZ target genes, including prooncogenic CCDN1 and CTGF, have also been shown to enhance the malignant phenotypes of MM cells. Together, these data indicate the Hippo pathway as a therapeutic target for the treatment of MM, and support the development of new strategies to effectively target the activation status of YAP1/TAZ as a promising therapeutic modality for this formidable disease.

Outcomes of the Multimodal Treatment of Malignant Pleural Mesiothelioma: The Role of Surgery

Background

The treatment of malignant pleural mesothelioma (MPM) is challenging, and multimodal treatment including surgery is recommended; however, the role of surgery is debated. The treatment outcomes of MPM in Korea have not been reported. We analyzed the outcomes of MPM in the context of multimodal treatment, including surgery.

Methods

The records of 29 patients with pathologically proven MPM from April 1998 to July 2015 were retrospectively reviewed. The treatment outcomes of the surgery and non-surgery groups were compared.

Results

The overall median survival time was 10.6 months, and the overall 3-year survival rate was 25%. No postoperative 30-day or in-hospital mortality occurred in the surgery group. Postoperative complications included tachyarrhythmia (n=4), pulmonary thromboembolism (n=1), pneumonia (n=1), chylothorax (n=1), and wound complications (n=3). The treatment outcomes between the surgery and non-surgery groups were not significantly different (3-year survival rate: 31.3% vs. 16.7%, respectively; p=0.47). In a subgroup analysis, there was no significant difference in the treatment outcomes between the extrapleural pneumonectomy group and the non-surgery group (3-year survival rate: 45.5% vs. 16.7%, respectively; p=0.23).

Conclusion

Multimodal treatment incorporating surgery did not show better outcomes than non-surgical treatment. A nationwide multicenter data registry and prospective randomized controlled studies are necessary to optimize the treatment of MPM.

Low-dose photon irradiation induces invasiveness through the SDF-1α/CXCR4 pathway in malignant mesothelioma cells

Background

Low-dose photon irradiation has repeatedly been suspected to increase a risk of promoting local recurrence of disease or even systemic dissemination. The purpose of this study was to investigate the motility of malignant pleural mesothelioma (MPM) cell lines after low-doses of photon irradiation and to elucidate the mechanism of the detected phenotype.

Methods

H28 and H226 MPM cells were examined in clonogenic survival experiments and migration assays with and without various doses of photon and carbon ion irradiation. C-X-C chemokine receptor type 4 (CXCR4), SDF-1α, β₁ integrin, α₃ integrin, and α₅ integrin expressions were analyzed by quantitative FACS analysis, ELISA and western blots. Apoptosis was assessed via Annexin-V-staining.

Results

The migration of MPM cells was stimulated by both fetal bovine serum and by stromal cell-derived factor 1α (SDF-1α). Low doses of photon irradiation (1 Gy and 2 Gy) suppressed clonogenicity, but promoted migration of both H28 and H226 cells through the SDF-1α/CXCR4 pathway. Hypermigration was inhibited by the administration of CXCR4 antagonist, AMD3100. In contrast, corresponding doses of carbon ion irradiation (0.3 Gy and 1 Gy) suppressed clonogenicity, but did not promote MPM cell migration.

Conclusion

Our findings suggest that the co-administration of photon irradiation and the CXCR4-antagonist AMD3100 or the use of carbon ions instead of photons may be possible solutions to reduce the risk of locoregional tumor recurrence after radiotherapy for MPM.

Malignant pleural mesothelioma: single-institution experience of 101 patients over a 15-year period

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare but aggressive neoplasm that typically originates from the mesothelial surfaces of the pleural cavity. Exposure to asbestos is the principal etiological agent of MPM. The disease is characterized by difficult stage classification and limited consensus on therapeutic approach. We have evaluated the experience with MPM in the Antwerp University Hospital over the past 15 years.

METHODS

A database was created with all patients diagnosed with or treated for a MPM between 2001 and 2015. A total of 101 patients were included on which different survival analyses were performed combined with a reproduction of demographic, clinical, histologic and therapeutic data, and these were compared to literature data.

RESULTS

Vast majority of our 101 patients were male (80%) with a median age of 66 years at diagnosis with predominantly epitheloid histology (81%). Overall median survival was 18.3 months and overall 1-, 2- and 5-year survival rates were 68%, 37% and 7%, respectively. Kaplan-Meier analysis showed a non-significant difference in survival between the several best (b) TNM-stages (p = .356). A significant difference in survival was observed in patients undergoing surgery versus no surgery (p = .008), between the different histological types (p < .0001) and treatment with chemotherapy alone versus chemotherapy with surgery (p < .0001). Smoking at diagnosis and epitheloid histology have been identified as significant prognostic factors in the multivariate Cox regression model (HR 3.13 and 0.53, respectively).

CONCLUSION

Descriptive and survival analysis of our patient database confirmed the limitations of the current staging system and were concordant with literature regarding MPM.

FAS and FASL genetic polymorphisms impact on clinical outcome of malignant pleural mesothelioma

Background

FAS-670 A>G (rs1800682) and FASL-844 C>T (rs763110) polymorphisms have been previously correlated with clinical outcome of non-small cell lung cancer (NSCLC) and breast and bladder cancers. We investigated the influence of these polymorphisms on clinical outcome of malignant pleural mesothelioma (MPM) patients.

Patients and methods

In this cohort study (NCT02269878), 68 epithelioid MPM Egyptian patients treated with first-line platinum-based chemotherapy were recruited in the period between April 2014 and May 2015. The genotype analysis was performed using TaqMan^® single-nucleotide polymorphism genotyping assay. The association between the selected polymorphisms and response rate, progression-free survival (PFS) and overall survival (OS) at 18 months was evaluated.

Results

The median age of patients was 55 years and 45.6% of them received platinum in combination with pemetrexed, while 54.4% received platinum in combination with gemcitabine. FASL-844 CC genotype was more common than expected in early-stage tumor (P=0.042). It was found that there was no association between the investigated polymorphisms and response rate or 18-month OS. However, the PFS rate at 18 months for FASL-844 CC genotype carriers was 45% versus 10.6% for FASL-844 CT/TT genotypes carriers (log-rank: 6.2; P=0.013). Also, the number of platinum-based cycles and tumor stage were found to be significant variables for PFS by univariate analysis (P≤0.001 and P=0.006, respectively). Stratified Cox regression showed that the carriers of FASL-844 CT/TT genotypes were still more susceptible to disease progression than carriers of FASL-844 CC genotype (adjusted HR =3.77, 95% CI: 1.34–10.62, P=0.012).

Conclusion

The results of this study suggest that FASL-844 C/T polymorphism could predict PFS in MPM patients receiving platinum-based chemotherapy; therefore, this should be further evaluated as a potential marker for the prediction of clinical outcome in patients with MPM.