3.5Surgery after MARS 2

Surgery for pleural mesothelioma has been one of the most argued-about parts of treatment for thirty years. The argument finished, for now, in 2024.

A British randomised trial called MARS 2 compared a major chest operation called extended pleurectomy decortication (EPD), in which a surgeon peels the diseased lining away from the lung, with chemotherapy alone. Patients who had EPD lived a shorter time, on average, than those who had chemotherapy on its own. They also had worse quality of life and more serious complications. The earlier MARS 1 trial had reached a similar verdict on a bigger operation, extrapleural pneumonectomy (EPP), which removes the whole lung along with the lining around it; EPP has not been routinely offered in the UK since.

The British Thoracic Society guideline on pleural mesothelioma, updated after MARS 2, is now clear: EPP and EPD should not be offered outside a clinical trial. A few specialist centres in the UK continue to recruit to trials testing variations of the operation in carefully selected patients. Those are research, not standard care.

What does still have a role:

• Talc pleurodesis. A procedure to stop fluid building up around your lung by deliberately sticking the two layers of lining together with sterile talc. Usually done during a thoracoscopy (a keyhole look inside the chest with a camera), it can settle weeks of breathlessness in one admission. Most patients with a recurrent pleural effusion will be offered this or the next option.
• Indwelling pleural catheter (IPC).Sometimes called a PleurX drain. A soft tube that stays in your chest wall under the skin so fluid can be drained at home by a district nurse, a few times a week. Useful when pleurodesis hasn’t worked, when the lung is ‘trapped’ and won’t re-expand, or when you’d rather avoid an in-patient stay.
• Video-assisted thoracoscopic surgery (VATS) for diagnosis.A small keyhole operation to take biopsies and drain fluid. This is how most mesothelioma is diagnosed now. It is not the same as EPD; it doesn’t try to remove the cancer.
• Targeted radiotherapy to a painful nodule or patch of chest wall (chapter 3.4). Not strictly surgery, but the alternative people often reach for to control localised pain.

If a private centre, UK or overseas, offers you EPD or EPP outside a trial, ask three things in writing before you agree:

1. Which trial protocol is this operation being delivered under, and where is it registered?
2. What are the MARS 2 results, and how does this centre’s outcome data compare?
3. Will the operation be discussed at my NHS mesothelioma MDT before it happens?

A confident, evidence-led surgeon will answer all three without hesitation. A refusal to give straight answers, or pressure to decide quickly, is the cue to walk away and ring Mesothelioma UK (0800 169 2409) for a second opinion.

The honest summary for almost everyone with pleural mesothelioma in 2026: the best chemotherapy and immunotherapy combination (chapter 3.3) does more for survival than the surgical operation does, with less harm. Surgery’s remaining job is symptom control — controlling fluid, easing pain — and clinical trials.