Breathlessness is one of the most difficult symptoms faced by some people diagnosed with pleural mesothelioma. Fluid can accumulate between the lung and chest wall, making breathing increasingly uncomfortable.
For certain patients, draining that fluid does not allow the lung to expand normally. Doctors sometimes describe this condition as trapped lung or non-expandable lung.
A peer-reviewed study published October 20, 2026, in the medical journal Thorax examined two approaches to managing this problem: placement of an indwelling pleural catheter and a surgical procedure known as video-assisted thoracoscopic partial pleurectomy/decortication.
The findings offer useful information about an important treatment decision, but the trial was too small to determine which approach produced better outcomes.
What is trapped lung?
Normally, the lung expands within the chest when a person breathes.
In pleural mesothelioma, cancer-related changes in the pleural tissues can restrict that movement. Some patients also develop recurrent pleural effusions—collections of fluid around the lung.
When fluid is drained but the lung remains unable to expand fully, the patient may have non-expandable lung.
This can complicate treatment because certain procedures intended to prevent fluid from returning depend on the lung expanding sufficiently.
Doctors must therefore consider whether drainage, a longer-term catheter, surgery, or another approach is likely to relieve symptoms while minimizing additional burdens.
What did the new study examine?
The MesoTRAP study was led by researchers including Dr. Robert Campbell Rintoul of the University of Cambridge and Royal Papworth Hospital, with collaborators at several UK institutions.
The investigators sought to compare two treatment strategies.
An indwelling pleural catheter is a small tube left in place to permit repeated drainage of fluid from around the lung. Depending on the patient's care plan, drainage can often be managed outside the hospital with appropriate instruction and support.
Video-assisted thoracoscopic partial pleurectomy/decortication is a surgical approach intended to remove or release affected pleural tissue and potentially improve lung expansion.
The procedures differ substantially in invasiveness, recovery demands, and possible complications.
The researchers intended to assess outcomes including breathlessness and pain to help determine whether a larger randomized study would be practical.
What did the researchers find?
Among the patients assessed during the study, trapped lung was identified in 110 of 988 patients—about 11%.
Across 17 participating centers, investigators randomized only 10 patients, compared with the planned enrollment of 38. Thirteen additional patients participated in an observational substudy.
Nine randomized patients recorded daily symptom measurements, but the results varied considerably.
The researchers concluded that the available data could not support a meaningful comparison of the two treatments.
Recruitment was particularly challenging because some patients were not medically fit enough to undergo surgery.
The investigators therefore concluded that, in the absence of stronger comparative evidence, the less invasive indwelling pleural catheter approach should be considered in accordance with existing clinical guidance.
The study did not demonstrate that pleural catheters extend survival, cure trapped lung, or provide superior symptom relief compared with surgery.
What do clinical guidelines recommend?
Existing guidance recognizes indwelling pleural catheters as an option for patients with malignant pleural effusions and non-expandable lung.
A joint clinical practice guideline from the American Thoracic Society, Society of Thoracic Surgeons, and Society of Thoracic Radiology recommends considering indwelling pleural catheters rather than chemical pleurodesis for patients with symptomatic malignant pleural effusions and non-expandable lung.
British Thoracic Society guidance likewise emphasizes patient preferences, clinical condition, and the limited evidence available for certain treatment decisions.
These guidelines address malignant pleural effusions more broadly; individual decisions for mesothelioma patients still require specialist assessment.
More recent mesothelioma-specific guidance from the American Society of Clinical Oncology also recognizes tunneled pleural catheters and other palliative approaches for selected patients who are not candidates for maximal surgical cytoreduction, while emphasizing multidisciplinary decision-making.
Does every mesothelioma patient with pleural fluid need a catheter?
No.
Some patients respond well to fluid drainage. Others may be candidates for different procedures, depending on lung expansion, symptoms, overall health, anticipated treatment, and personal preferences.
A catheter can also create responsibilities and risks, including infection, blockage, discomfort, and the need for drainage support.
Surgical intervention has its own risks and may not be suitable for someone with limited cardiopulmonary reserve or advanced illness.
Determining which option is appropriate is a medical decision that should involve clinicians familiar with pleural disease and mesothelioma.
Questions patients and families can ask
When someone with mesothelioma experiences repeated fluid accumulation or persistent breathlessness, practical questions for the medical team include:
- Is the lung expanding normally after fluid drainage?
- Is breathlessness primarily related to pleural fluid, or could other causes be contributing?
- Would a longer-term pleural catheter help manage symptoms at home?
- Would surgery offer a realistic benefit, and what risks would it involve?
- Who would assist with catheter care, drainage, and management of complications?
These questions can help patients understand the purpose of a recommended procedure and the alternatives available.
H&S provides additional background in Mesothelioma Treatment Options, Finding a Mesothelioma Specialist, and After a Mesothelioma Diagnosis.
Why symptom management is an important part of mesothelioma treatment
New cancer drugs and clinical trials receive considerable attention, but managing breathlessness, pain, fatigue, and recurrent fluid can be equally important to a patient's everyday experience.
Supportive and palliative care are not necessarily alternatives to active cancer treatment. They can be provided alongside chemotherapy, immunotherapy, radiation, or other treatment approaches.
The MesoTRAP study is a reminder that better mesothelioma care involves both investigating cancer-directed treatments and addressing the immediate symptoms affecting patients and families.
Its findings do not establish a new treatment standard. They reinforce the importance of individualized clinical decisions and the need for additional research.
Original sources and further information
- Thorax — MesoTRAP original study, October 20, 2026
- University of Bristol — study abstract and research record
- ClinicalTrials.gov — MesoTRAP, NCT03412357
- British Thoracic Society — Pleural Disease guidance
- American Thoracic Society and partner societies — malignant pleural effusion guideline
- American Society of Clinical Oncology — Treatment of Pleural Mesothelioma guideline update
Medical information notice: Humpleby & Strauss, P.C. is a law firm, not a medical provider. This article provides general educational information and does not constitute medical advice. Diagnosis, symptom management, and treatment decisions should be discussed with qualified medical professionals familiar with the patient's condition. Editorial standards.