What is pleural mesothelioma?
Pleural mesothelioma is a cancer that starts in the pleura, the thin membrane that lines the inside of the chest wall and covers the lungs. It is different from lung cancer, which begins within the lung itself. The tumour usually spreads along the pleural surface, encasing the lung and producing fluid around it (a pleural effusion, see pleural disease).
Mesothelioma is rare. It is strongly linked to past asbestos exposure and typically appears 20 to 50 years after that exposure. In India, asbestos-cement sheets, pipes, brake linings and shipbreaking have been important sources, so the number of cases may increase in future.
Diagnosis is handled by the pulmonology team, while treatment is planned in a multidisciplinary setting with medical oncology, thoracic surgery, radiation oncology and palliative care.
Symptoms of pleural mesothelioma
Symptoms tend to develop gradually and are often attributed to other causes at first:
- Breathlessness: usually due to fluid collecting around one lung.
- Chest pain: a dull, persistent ache in the chest wall or shoulder, which may become severe.
- Weight loss and loss of appetite.
- Fatigue, sweating and fever.
- Persistent cough.
Any one-sided pleural effusion in an adult, particularly with chest pain or a history of asbestos exposure, needs thorough investigation rather than repeated drainage alone.
Causes and risk factors
Asbestos exposure is the main cause. Fibres that are inhaled travel to the pleura and cause long-term inflammation and genetic damage. Those at risk include:
- Workers in asbestos mining, asbestos-cement manufacture, construction, insulation, shipbreaking, railways and brake repair
- Family members exposed to fibres carried home on work clothes
- People living near asbestos factories or handling damaged asbestos roofing
There is no known safe level of exposure, and the risk does not depend on smoking, although smoking greatly increases the risk of asbestos-related lung cancer. Other rare causes include previous radiotherapy to the chest and inherited BAP1 gene mutations. Some patients have no identifiable exposure.
How mesothelioma is diagnosed
Mesothelioma can be difficult to diagnose, and pleural fluid tests alone are often inconclusive. A tissue biopsy is usually needed.
| Test | What it shows |
|---|---|
| Chest X-ray and ultrasound | Pleural fluid and thickening, and guides safe sampling |
| Contrast CT chest | Nodular or circumferential pleural thickening and the extent of disease |
| Pleural fluid analysis | Cell type and exclusion of infection, including tuberculosis |
| Medical thoracoscopy or CT-guided biopsy | Tissue for diagnosis and subtyping |
| PET-CT and other staging scans | Spread beyond the pleura, to help plan treatment |
Medical thoracoscopy, an interventional pulmonology procedure, allows the pleura to be inspected directly, adequate biopsies to be taken, and fluid to be drained in a single sitting. Biopsy samples are classified into epithelioid, sarcomatoid or biphasic types, which influences treatment and outlook. In India, pleural effusion is commonly due to tuberculosis, so both conditions are carefully considered.
Treatment of pleural mesothelioma
Treatment is decided in a multidisciplinary tumour board and tailored to the tumour type, stage, overall fitness and the patient's wishes.
Systemic therapy
Immunotherapy with the combination of nivolumab and ipilimumab is a standard first-line option, particularly for non-epithelioid types. Chemotherapy with a platinum drug and pemetrexed, sometimes combined with immunotherapy, is another established approach.
Surgery and radiotherapy
Surgery is offered only to carefully selected patients at specialist centres. Radiotherapy may be used to relieve pain.
Controlling fluid and symptoms
Recurrent fluid is managed with talc pleurodesis or an indwelling pleural catheter, allowing drainage at home and fewer hospital visits. Early involvement of palliative care helps control pain and breathlessness and improves quality of life. Clinical trials may be an option for some patients.
Outlook and support
Mesothelioma is a serious cancer that is rarely curable, but treatment can control the disease, relieve symptoms and extend life. Outlook is generally better for the epithelioid type and for patients who are fitter at diagnosis. Regular follow-up with imaging and symptom review continues throughout. Patients and families are encouraged to discuss their goals of care openly, and to keep records of past asbestos exposure, which may be relevant for occupational compensation.
When to seek urgent care
Seek urgent medical attention for rapidly worsening breathlessness, severe chest pain not controlled by usual medicines, fever with an indwelling pleural catheter or redness at its site, coughing up blood, or fainting. Patients receiving immunotherapy should report new diarrhoea, rash, cough or breathlessness promptly, as these may be treatment side effects.
Frequently asked questions
Is mesothelioma the same as lung cancer?
No. Mesothelioma starts in the pleura, the lining around the lung, whereas lung cancer starts in the lung tissue or airways. They are treated differently.
I was exposed to asbestos years ago. Should I be screened?
There is no proven screening test for mesothelioma. People with past asbestos exposure should stop smoking, mention the exposure to their doctor, and seek assessment for any persistent breathlessness, chest pain or chest fluid.
Can mesothelioma be cured?
Cure is uncommon, but modern immunotherapy, chemotherapy and symptom control can keep the disease in check, improve symptoms and extend life for many patients.
Why do I need a thoracoscopy when fluid has already been tested?
Fluid tests often cannot confirm or rule out mesothelioma. Thoracoscopy allows biopsies to be taken directly from the pleura and the fluid to be drained in the same procedure.
What is an indwelling pleural catheter?
It is a thin, soft tube placed in the chest under local anaesthetic, through which fluid can be drained at home. It reduces repeated hospital procedures and helps control breathlessness.
Is mesothelioma inherited?
Most cases are caused by asbestos exposure. A small number are linked to inherited BAP1 gene changes, and genetic counselling may be offered where the family history suggests this.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.