Occupational Medicine & Health Affairs
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Pleural mesothelioma; Asbestos exposure; Cancer; Diagnosis; Treatment; Prognosis

Introduction

Pleural mesothelioma is a malignant neoplasm that arises from the mesothelial cells lining the pleural cavity. Its association with asbestos exposure makes it a significant public health concern, especially in industries where asbestos was commonly used, such as construction, shipbuilding, and manufacturing. The disease typically presents years or even decades after initial exposure, complicating early diagnosis and treatment.

In this article, we will explore the characteristics of pleural mesothelioma, focusing on its causes, symptoms, diagnostic approaches, treatment modalities, and the challenges faced by patients and healthcare providers [1].

Methodology

Etiology and risk factors

The primary cause of pleural mesothelioma is exposure to asbestos, a naturally occurring mineral that was widely used for its insulating and fire-resistant properties. When asbestos fibers are inhaled, they can become lodged in the pleura, leading to inflammation and cellular damage over time. Other risk factors for developing pleural mesothelioma include:

Occupational exposure: Workers in industries such as construction, shipbuilding, and manufacturing are at higher risk due to direct contact with asbestos-containing materials [2].

Environmental exposure: Individuals living near asbestos mines or factories may be exposed to airborne asbestos fibers.

Genetic predisposition: Certain genetic factors may increase susceptibility to developing mesothelioma.

Smoking: While smoking does not directly cause pleural mesothelioma, it can exacerbate the risk in individuals already exposed to asbestos [3].

Pathophysiology

Pleural mesothelioma originates from the mesothelial cells, which line the pleural cavity. The disease is characterized by the proliferation of these cells, leading to the formation of tumors. The tumors can invade surrounding tissues and organs, including the lungs and chest wall [4].

There are three main histological subtypes of pleural mesothelioma:

Epithelioid Mesothelioma: This is the most common subtype, associated with better prognosis compared to other forms.

Sarcomatoid mesothelioma: This subtype is less common and generally has a poorer prognosis due to its aggressive nature.

Biphasic mesothelioma: This subtype contains both epithelioid and sarcomatoid cells, and its prognosis varies depending on the predominance of each type [5].

Clinical presentation

Symptoms of pleural mesothelioma often develop insidiously and can be mistaken for other respiratory conditions. Common symptoms include:

Pleural effusion: Accumulation of fluid in the pleural cavity is a hallmark of pleural mesothelioma and can cause difficulty breathing and chest pain.

Chest pain: Patients may experience persistent, localized chest pain that can radiate to the shoulder or back

Shortness of breath: This symptom may result from pleural effusion or tumor growth compressing the lungs.

Cough: A persistent dry cough is often reported by patients [6].

Fatigue and weight loss: Generalized fatigue and unexplained weight loss are common systemic symptoms.

Due to the nonspecific nature of these symptoms, diagnosis is often delayed, contributing to a poor prognosis.

Diagnostic approaches

Diagnosing pleural mesothelioma typically involves a combination of imaging studies, laboratory tests, and histological examination. Common diagnostic methods include:

Imaging studies:

Chest X-ray: This initial imaging test can reveal pleural effusions or abnormalities in the pleura [7].

CT scan: A more detailed imaging technique that helps assess the extent of the disease and identify tumors.

MRI: Used to provide detailed images of soft tissues and assess the involvement of surrounding structures.

Biopsy:

Thoracentesis: A procedure to extract pleural fluid for cytological examination, which can indicate the presence of cancer cells.

Needle biopsy: A fine needle is used to obtain a tissue sample from the pleura for histological analysis.

Surgical biopsy: In some cases, a more invasive surgical procedure may be required to obtain a definitive diagnosis [8].

Molecular testing:

Molecular markers, such as biomarkers and genetic mutations, can aid in diagnosis and provide insights into prognosis and treatment options.

Treatment options

The treatment of pleural mesothelioma depends on the stage of the disease, the patient’s overall health, and the histological subtype. Treatment modalities include:

Surgery:

Pleurectomy/decortication (P/D): This surgical procedure involves removing the pleura and any visible tumor, aiming to relieve symptoms and improve quality of life [9].

Extrapleural pneumonectomy (EPP): Involves removing the entire affected lung, pleura, and nearby tissues. This is a more aggressive approach and is suitable for early-stage patients.

Chemotherapy: Chemotherapy is often used as a primary treatment for advanced pleural mesothelioma. Common regimens include the combination of pemetrexed and cisplatin, which has shown efficacy in improving survival rates.

Radiation therapy: Radiation may be used to target specific areas of tumor growth, particularly in palliative settings to relieve symptoms [10].

Immunotherapy: Recent advancements in immunotherapy have shown promise in treating pleural mesothelioma. Agents such as nivolumab and pembrolizumab are being studied in clinical trials, with some success in improving outcomes for patients.

Clinical trials: Patients are encouraged to consider participating in clinical trials that explore new treatments and therapies. These trials may offer access to innovative approaches that are not yet widely available.

Prognosis

The prognosis for pleural mesothelioma is generally poor, with a median survival rate of about 12 to 21 months post-diagnosis. Several factors influence prognosis, including:

Stage of disease: Patients diagnosed at earlier stages generally have better outcomes compared to those with advanced disease.

Histological subtype: Epithelioid mesothelioma typically has a better prognosis than sarcomatoid or biphasic forms.

Patient health: Overall health, age, and response to treatment also play significant roles in determining survival rates.

Challenges in early detection

One of the significant challenges in managing pleural mesothelioma is its late presentation. Many patients are diagnosed at an advanced stage due to the prolonged latency period following asbestos exposure. This delay can be attributed to several factors:

Nonspecific symptoms: Symptoms can mimic other respiratory conditions, leading to misdiagnosis and treatment delays.

Lack of awareness: There is often insufficient public awareness about the risks of asbestos exposure and the signs of pleural mesothelioma.

Limited screening methods: Currently, there are no standardized screening protocols for high-risk populations, making early detection difficult.

The impact of asbestos regulations

Regulations on asbestos use have evolved significantly over the years. In many countries, including the United States, the use of asbestos has been banned or heavily restricted. However, the legacy of asbestos exposure continues to impact public health.

Ongoing awareness campaigns and legislative efforts aim to educate the public about the dangers of asbestos and promote safer workplace practices. As regulations evolve, it is crucial for industries to implement strict safety measures to prevent future exposures.

Research and future directions

Research in pleural mesothelioma is ongoing, focusing on various aspects, including:

Novel therapies: Investigating new chemotherapy agents, targeted therapies, and immunotherapies to improve treatment outcomes.

Biomarkers: Identifying biomarkers that can help with early detection and prognosis, enabling personalized treatment approaches.

Asbestos alternatives: Developing and promoting safer materials to reduce reliance on asbestos in construction and manufacturing.

Patient support: Enhancing support services for patients and their families to navigate the complexities of diagnosis, treatment, and coping with the disease.

Discussion

Pleural mesothelioma remains a significant challenge in oncology due to its association with asbestos exposure and the complexity of its diagnosis and treatment. Awareness and education about the risks of asbestos and the signs of pleural mesothelioma are crucial for early detection and improved outcomes.

Healthcare providers play a pivotal role in identifying at-risk populations and implementing screening protocols, particularly for those with a history of asbestos exposure. The integration of multidisciplinary care teams is essential to address the various aspects of treatment and support for patients.

Ongoing research is vital to understanding the molecular mechanisms of pleural mesothelioma and developing innovative therapies. Collaboration between researchers, clinicians, and advocacy groups will help drive progress in improving patient outcomes and addressing the needs of those affected by this devastating disease.

Conclusion

Pleural mesothelioma is a complex and aggressive cancer with significant implications for affected individuals and public health. Its strong association with asbestos exposure highlights the need for continued vigilance in preventing exposure and promoting awareness of the disease.

Understanding the etiology, clinical presentation, diagnostic methods, and treatment options is essential for healthcare professionals to provide optimal care

1. Wei J, Goldberg MB, Burland V, Venkatesan MM, Deng W, et al. (2003) Complete genome sequence and comparative genomics of Shigella flexneri serotype 2a strain 2457T. Infect Immun 71: 2775-2786.

Google Scholar, Crossref, Indexed at

2. Kuo CY, Su LH, Perera J, Carlos C, Tan BH, et al. (2008) Antimicrobial susceptibility of Shigella isolates in eight Asian countries, 2001-2004. J Microbiol Immunol Infect; 41: 107-11.

Google Scholar, Indexed at

3. Gupta A, Polyak CS, Bishop RD, Sobel J, Mintz ED (2004) Laboratory-confirmed shigellosis in the United States, 1989- 2002: Epidemiologic trends and patterns. Clin Infect Dis 38: 1372-1377.

Google Scholar, Crossref, Indexed at

4. Murugesan P, Revathi K, Elayaraja S, Vijayalakshmi S, Balasubramanian T (2012) Distribution of enteric bacteria in the sediments of Parangipettai and Cuddalore coast of India. J Environ Biol 33: 705-11.

Google Scholar, Indexed at

5. Torres AG (2004) Current aspects of Shigella pathogenesis. Rev Latinoam Microbiol 46: 89-97.

Google Scholar, Indexed at

6. Bhattacharya D, Bhattacharya H, Thamizhmani R, Sayi DS, Reesu R, et al. (2014) Shigellosis in Bay of Bengal Islands, India: Clinical and seasonal patterns, surveillance of antibiotic susceptibility patterns, and molecular characterization of multidrug-resistant Shigella strains isolated during a 6-year period from 2006 to 2011. Eur J Clin Microbiol Infect Dis; 33: 157-170.

Google Scholar, Crossref, Indexed at

7. Bachand N, Ravel A, Onanga R, Arsenault J, Gonzalez JP (2012) Public health significance of zoonotic bacterial pathogens from bushmeat sold in urban markets of Gabon, Central Africa. J Wildl Dis 48: 785-789.

Google Scholar, Crossref, Indexed at

8. Saeed A, Abd H, Edvinsson B, Sandström G (2009) Acanthamoeba castellanii an environmental host for Shigella dysenteriae and Shigella sonnei. Arch Microbiol 191: 83-88.

Google Scholar, Crossref, Indexed at

9. Iwamoto M, Ayers T, Mahon BE, Swerdlow DL (2010) Epidemiology of seafood-associated infections in the United States. Clin Microbiol Rev 23: 399-411.

Google Scholar, Crossref, Indexed at

10. Von-Seidlein L, Kim DR, Ali M, Lee HH, Wang X, et al. (2006) A multicentre study of Shigella diarrhoea in six Asian countries: Disease burden, clinical manifestations, and microbiology. PLoS Med 3: e353.

Google Scholar, Crossref, Indexed at