Continuing Education Activity
Malignant mesothelioma is a rare growth of mesothelial cells strongly associated with asbestos exposure. Mesothelial cells form the lining layers of the viscera. Mesothelioma can occur at any mesothelial layer such as the peritoneum or pericardium. The pleural layer is by far the most commonly affected, giving rise to malignant pleural mesothelioma. This activity reviews the cause, pathophysiology and presentation of malignant mesotheloma and highlights the role of the interprofessional team in its management.
Objectives:
Describe the pathophysiology of malignant mesothelioma.
Review the workup of a patient with suspected malignant mesothelioma.
Summarize the treatment options for malignant mesothelioma.
Outline the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by malignant mesothelioma.
Introduction
Malignant mesothelioma is a rare growth of mesothelial cells strongly associated with asbestos exposure. Mesothelial cells form the lining layers of the viscera. Mesothelioma can occur at any mesothelial layer such as the peritoneum or pericardium. The pleural layer is by far the most commonly affected, giving rise to malignant pleural mesothelioma. [1][2][3][4]The subtypes of asbestos strongly associated with malignant mesothelioma are the amosite and crocidolite asbestos.
Etiology
Malignant pleural mesotheliomais primarily linked to asbestos exposure, with some suggesting that asbestos inhalation causes repeated pleural inflammation, interference with mitosis, activation of proto-oncogenes, and free radical production. Other reports indicate associations with ionizing radiation, such as mantle radiation for Hodgkin lymphoma, or a germline mutation of BRCA 1 Associated Protein (BAP1). [5]Smoking is not linked with malignant pleural mesothelioma, though smoking and asbestos exposure significantly increase the risk of lung cancer.
Professions associated with exposure to asbestos include:
Shipbuilding
Mining
Ceramics
Cement manufacturer with asbestos
Auto partsmanufacturer, especially that of brake lining
Paper mill worker
Insulation work
Railroad repair
There is no evidence that alcohol, tobacco, or dietary intake is involved in malignant pleural mesothelioma.
It is believed that particular genetic makeup or changes may make people more susceptible tothis disease. Research shows that the loss of one copy of chromosome 22 is commonly seen in patients with malignant pleural mesothelioma. Other chromosomal anomalies that have been identified include deletions in chromosomal arms 3p, 1p, 6q, and 9p.
Epidemiology
Malignant pleural mesotheliomaincidence is approximately 2500 new cases per year in the United States. By comparison, lung cancer incidence is more than 160,000 new cases per year. Mostmalignant pleural mesotheliomacases in the United States have a history of asbestos exposure.
Median survival is roughly 1 year, with long-term survival being extremely rare.Malignant pleural mesotheliomaalso predominantly affects males. It usually occurs after the fifth decade of life with an average age at diagnosis of 72 and a history of asbestos exposure of 2 to 4 decades before the diagnosis of disease.Cases havebeen reportedin children, but these are not related to asbestos exposure.
Malignant pleural mesothelioma occurs more frequently in some countries like China where asbestos is still widely used with little oversight. On the other hand, in other places like Hong Kong, asbestos exposure is still high, butmalignant pleural mesotheliomarates are low. The reason for these differences remains unknown.
Pathophysiology
The three types of mesothelioma are epithelioid, sarcomatoid, and mixed. The epithelioid type is associated with better outcomes. The tumor is often multifocal, forming multiple nodules starting with the parietal pleura. Spread occurs locally in the visceral pleura before extending to the chest wall, diaphragm, or mediastinum. Regional lymph node spread begins with the bronchopulmonary or hilar lymph nodes before moving to the carinal, internal mammary or peridiaphragmatic nodes.
The pattern of nodal metastases is different from that seen in lung cancer. With malignant pleural mesothelioma, there is a direct local invasion of the lymph nodes. Overall, the involvement of lymph nodes inmalignant pleural mesotheliomais not common.
Histopathology
Analysis of excised tissue usually reveals large nodules on the pleural surface. Three histological subtypes that are involved inmalignant pleural mesotheliomainclude sarcomatous, mixed, andepithelial which has the best prognosis.
History and Physical
Malignant pleural mesothelioma usually presents with chest pain and dyspnea. Dyspnea suggests the presence of pleural effusion, the most common initial finding, seen in about 90% of patients. Nonspecific symptoms such as unintentional weight loss, appetite loss, cough, fatigue, and chest wall mass may also occur.
Evaluation
The evaluation includes a thorax CT scan with intravenous contrast, a thoracoscopic pleural biopsy, and thoracentesis of pleural effusion, if present, with cytologic analysis. [6][7][8]Malignant pleural mesothelioma needs to be distinguished from other conditions. These conditions include benign pleural diseases as well as metastasis of other tumors such as lung adenocarcinoma or chest wall sarcoma. A chest CT scan will show focal areas of pleural thickening, with a large invasive mass present in late-stage disease. PET scans may be used to screen for metastatic disease, while MRI and laparoscopy can be used to evaluate diaphragmatic invasion.
Megakaryocyte potentiating factor is used as a serum biomarker for malignant pleural mesothelioma.
The cardiologist must clear all patients deemedcandidates for surgery. A stress test should be performed, and lung function should be optimized.
Treatment / Management
Using National Comprehensive Cancer Network Guidelines, treatment depends upon tumor staging for the feasibility of surgical resection with Stage III-IV malignant pleural mesothelioma being considered unresectable. Ultimately less than a third of patients are candidates for definitive resection. It is recommended that mesothelioma be treated by a multidisciplinary team at a high volume center.[6][9][10][11]
Differential Diagnosis
The differential diagnosis for malignant pleural mesothelioma includes:
Non-small cell lung cancer
Small cell lung cancer
Drug-induced lung complications
Benign pleural mass
Lung infection
Lung fibrosis
Surgical Oncology
For resectable disease, surgical options include either pleurectomy/decortication (P/D) in early stages, or extrapleural pneumonectomy (EPP; resection of pleura, lung, pericardium, and diaphragm) when attempting curative resection. This choice is controversial as limited evidence is available. EPP is associated with high mortality compared with P/D, though this may be due to the patient population selected to undergo each. High-dose adjuvant radiotherapy is used after EPP to improve local control. There have been some attempts to use prophylactic radiotherapy, but this remains controversial with no clear benefit established. Systemic chemotherapy can be given as neoadjuvant or adjuvant therapy and is usually platinum-based. Neoadjuvant chemotherapy may increase survival if there is a response, but overall efficacy is unproven. Adjuvant chemotherapy is difficult because of the toxicities of the medications after the stress of extensive surgery.
Radiation Oncology
Radiation therapy is used, but the results are extremely poor. The treatment does not affect survival but may provide palliation in patients with chest wall metastases.
Medical Oncology
For unresectable disease, platinum-based chemotherapy agents such as cisplatin are the first treatment option. Malignant pleural mesothelioma is more resistant to chemotherapy, however, and so there is an unclear survival benefit. For example, the combination of gemcitabine and cisplatin has a response rate of between 12% and 48%, but median overall survival still is only 9 to 13 months. Biologic and antiangiogenic therapies are being investigated as well.
Staging
Stage I: A totally resected mass confined within the capsule of the parietal pleura. There is no lymphadenopathy.
Stage II: Has all the features of a stage I lesion, but the margins are positive after resection. There may be intrapleural lymphadenopathy.
Stage III: There is a local invasion of the mass into the mediastinum, pericardium, chest wall or peritoneum. Lymphadenopathy is common.
Stage IV: The presence of distant metastatic disease.
Prognosis
Despite advances, the prognosis for most malignant pleural mesothelioma patients is grim; death is inevitable within 4 to 6 months. With treatment, some patients may survive 15 to 18 months. Rarely,5-year survivals have been reported. The biggest problem is tumor recurrence, especially in patients managed with surgery.
Patients undergoing surgery may have slightly longer survival, but they also develop many complications related to the procedure. These complications include arrhythmias, wound infection, deep vein thrombosis, air leak, respiratory failure, postoperative bleeding, and myocardial infarction. Poor prognostic factors include nonepithelial histology, poor performance status, age over 75, dyspnea and chest pain on presentation, elevated lactate dehydrogenase and low hemoglobin on presentation, and weight loss.
Complications
Complications can arisebecause of malignant pleuralmesothelioma itself, chemotherapy, and surgery. The surgery is associated with extremely high morbidity and mortality. Some of thesecomplications include:
Myocardial infarction
Dependency on the ventilator
Bronchial air leak
Postpneumonectomy stump failure
Multiorgan failure
Wound infection
Renal failure from cisplatinum
Pancytopenia from chemotherapy
Postoperative and Rehabilitation Care
Patients are encouraged to enter a rehab program to recover functionality after treatment. A gooddiet should be encouraged as most patients are frail and emaciated. Home oxygen is often required.
Pearls and Other Issues
Malignant pleural mesothelioma is a life-threatening malignancy. Even with treatment, it has a very poor outcome.
The epithelial histology has a better prognosis than other histologies.
Patients often present with dyspnea and weight loss.
A pleural effusion is often present on the initial chest X-ray.
Diagnosis can be difficult.Thorough immunostaining techniques must be employed.
The ideal treatment is surgery for a localized disease, but most patients are not candidates for the procedure. The surgery is also associated with severe complications.
Cisplatinum-based chemotherapy is used for advanced cases.
Radiation has not been shownto affect survival but may play a role in palliation.
Enhancing Healthcare Team Outcomes
Malignant mesothelioma is a system disorder that requires an interprofessional team of doctors including an oncologist, thoracic surgeon, pulmonary specialist, radiation oncologist, and pain specialist. The cancer is difficult to diagnose and all the currently available treatments have not had any major impact on life expectancy. Using National Comprehensive Cancer Network Guidelines, treatment depends upon tumor staging for the feasibility of surgical resection with Stage III-IV malignant pleural mesothelioma being considered unresectable. Ultimately less than a third of patients are candidates for definitive resection. It is recommended that mesotheliomabetreated by an interprofessional team at a high volume center. These patients may benefit from palliative or hospice care as most are frail and have only months to live at the time of diagnosis. Even though surgery is done, it is associated with severe life-threateningcomplications. Most patients with this cancer are dead within 12 months.[12][13]
References
- 1.
Zha L, Kitamura Y, Kitamura T, Liu R, Shima M, Kurumatani N, Nakaya T, Goji J, Sobue T. Population-based cohort study on health effects of asbestos exposure in Japan. Cancer Sci. 2019 Mar;110(3):1076-1084. [PMC free article: PMC6398882] [PubMed: 30618090]
- 2.
Tazzari M, Brich S, Tuccitto A, Bozzi F, Beretta V, Spagnuolo RD, Negri T, Stacchiotti S, Deraco M, Baratti D, Camisaschi C, Villa A, Vergani B, Rivoltini L, Pilotti S, Castelli C. Complex Immune Contextures Characterise Malignant Peritoneal Mesothelioma: Loss of Adaptive Immunological Signature in the More Aggressive Histological Types. J Immunol Res. 2018;2018:5804230. [PMC free article: PMC6231377] [PubMed: 30510965]
- 3.
Yoneda K, Kuwata T, Chikaishi Y, Mori M, Kanayama M, Takenaka M, Oka S, Hirai A, Imanishi N, Kuroda K, Ichiki Y, Ohnaga T, Tanaka F. Detection of circulating tumor cells with a novel microfluidic system in malignant pleural mesothelioma. Cancer Sci. 2019 Feb;110(2):726-733. [PMC free article: PMC6361567] [PubMed: 30499156]
- 4.
Berzenji L, Van Schil P. Multimodality treatment of malignant pleural mesothelioma. F1000Res. 2018;7 [PMC free article: PMC6198256] [PubMed: 30410726]
- 5.
Mlika M, Lamzirbi O, Limam M, Mejri N, Ben Saad S, Chaouch N, Ben Miled K, Marghli A, Mezni F. [Clinical and pathological profile of the pleural malignant mesothelioma: A retrospective study about 30cases]. Rev Pneumol Clin. 2018 Dec;74(6):427-435. [PubMed: 30293912]
- 6.
Ettinger DS, Wood DE, Akerley W, Bazhenova LA, Borghaei H, Camidge DR, Cheney RT, Chirieac LR, D'Amico TA, Dilling T, Dobelbower M, Govindan R, Hennon M, Horn L, Jahan TM, Komaki R, Lackner RP, Lanuti M, Lilenbaum R, Lin J, Loo BW, Martins R, Otterson GA, Patel JD, Pisters KM, Reckamp K, Riely GJ, Schild SE, Shapiro TA, Sharma N, Swanson SJ, Stevenson J, Tauer K, Yang SC, Gregory K, Hughes M. NCCN Guidelines Insights: Malignant Pleural Mesothelioma, Version 3.2016. J Natl Compr Canc Netw. 2016 Jul;14(7):825-36. [PMC free article: PMC10187059] [PubMed: 27407123]
- 7.
Woolhouse I, Maskell NA. Introducing the new BTS guideline: the investigation and management of pleural malignant mesothelioma. Thorax. 2018 Mar;73(3):210-212. [PubMed: 29444989]
- 8.
Odisio EG, Marom EM, Shroff GS, Wu CC, Benveniste APA, Truong MT, Benveniste MF. Malignant Pleural Mesothelioma: Diagnosis, Staging, Pitfalls and Follow-up. Semin Ultrasound CT MR. 2017 Dec;38(6):559-570. [PubMed: 29179896]
- 9.
Butnor KJ, Brownlee NA, Mahar A, Pavlisko EN, Sp*rn TA, Roggli VL. Diffuse malignant mesothelioma and synchronous lung cancer: A clinicopathological study of 18 cases. Lung Cancer. 2016 May;95:1-7. [PubMed: 27040844]
- 10.
Churg A, Attanoos R, Borczuk AC, Chirieac LR, Galateau-Sallé F, Gibbs A, Henderson D, Roggli V, Rusch V, Judge MJ, Srigley JR. Dataset for Reporting of Malignant Mesothelioma of the Pleura or Peritoneum: Recommendations From the International Collaboration on Cancer Reporting (ICCR). Arch Pathol Lab Med. 2016 Oct;140(10):1104-10. [PMC free article: PMC5267638] [PubMed: 27031777]
- 11.
Chen R, Lou J, Zhang X. [Guidelines for pathologic diagnosis of malignant mesothelioma--2012 update of the consensus statement from the International Mesothelioma Interest Group]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2015 Nov;33(11):860-3. [PubMed: 26887278]
- 12.
Fournel L, Janet-Vendroux A, Canny-Hamelin E, Mansuet-Lupo A, Guinet C, Bobbio A, Damotte D, Alifano M. [Malignant pleural mesothelioma: The role of surgery]. Rev Pneumol Clin. 2018 Oct;74(5):351-358. [PubMed: 30316650]
- 13.
Bibby AC, Maskell NA. Current treatments and trials in malignant pleural mesothelioma. Clin Respir J. 2018 Jul;12(7):2161-2169. [PubMed: 30129116]
Disclosure: Sumeet Jain declares no relevant financial relationships with ineligible companies.
Disclosure: Jason Wallen declares no relevant financial relationships with ineligible companies.
