Treatment of Pleural Mesothelioma
For newly diagnosed pleural mesothelioma, ipilimumab plus nivolumab should be offered as first-line systemic therapy for up to 2 years, with this being the mandatory choice for nonepithelioid histology, while epithelioid histology may alternatively receive pembrolizumab with pemetrexed plus platinum-based chemotherapy. 1
First-Line Systemic Therapy by Histologic Subtype
The 2025 ASCO guidelines fundamentally restructure treatment based on histology:
Nonepithelioid Mesothelioma (Biphasic or Sarcomatoid)
- Ipilimumab plus nivolumab is the required first-line treatment 1
- This represents a strong recommendation with high-quality evidence
- Duration: up to 2 years in absence of progression or intolerable toxicity 1
- These patients should NOT be offered maximal surgical cytoreduction 1
Epithelioid Mesothelioma
You have two evidence-based options:
- Ipilimumab plus nivolumab (strong recommendation, high-quality evidence) 1
- Pembrolizumab with pemetrexed plus platinum-based chemotherapy (strong recommendation, high-quality evidence) 1
The choice between these depends on:
- Patient preference regarding toxicity profiles
- Institutional availability
- Comorbidities affecting tolerance of combination chemoimmunotherapy
Critical caveat: Do NOT use PD-L1, TMB, or MSI testing to choose between chemotherapy and immunotherapy—these biomarkers have no validated role in treatment selection for mesothelioma 1.
Role of Surgery in Multimodality Treatment
Surgery should only be considered in highly selected patients meeting ALL of the following criteria 1:
- Epithelioid histology only (sarcomatoid is an absolute contraindication)
- Adequate cardiopulmonary functional reserve
- No extrathoracic disease
- Ability to receive multimodality treatment (neoadjuvant or adjuvant therapy)
- Good performance status
- Disease amenable to complete macroscopic resection
When surgery is appropriate, pleurectomy/decortication (P/D) or extended P/D is the preferred approach over extrapleural pneumonectomy 1. The MARS trial demonstrated worse outcomes with EPP (HR 2.75,95% CI 1.21-6.26) 2, though this small feasibility study was not powered for survival.
Recent data from a 152-patient cohort showed median overall survival of 31.7 months with P/D-based multimodality therapy (35.0 months for epithelioid, 18.3 months for nonepithelioid), with zero 90-day mortality 3. However, histologic type remained the only independent predictor of survival regardless of resection status or stage.
Important surgical exclusions 1:
- Sarcomatoid histology
- Contralateral mediastinal or supraclavicular lymph nodes
- Multilevel chest wall infiltration
- Inadequate cardiopulmonary reserve
Patients Ineligible for Surgery
For patients with symptomatic pleural effusion who are not surgical candidates 1:
- Offer systemic therapy as outlined above
- Consider palliative procedures (percutaneous catheter drainage)
- For asymptomatic patients with minimal pleural disease, a trial of close observation before initiating systemic therapy may be offered 1
Second-Line and Beyond
After Prior Chemotherapy
- Double-agent immunotherapy may be offered (moderate evidence, strong recommendation) 1
- Single-agent immunotherapy may be offered (high-quality evidence, strong recommendation) 1
After Prior Immunotherapy
- For patients with initial disease control whose disease progressed after completing immunotherapy, retreatment with immunotherapy may be offered (very low evidence, conditional recommendation) 1
- Alternatively, pemetrexed plus platinum-based chemotherapy if not previously received 1
- Vinorelbine or gemcitabine are commonly used options 4
Managing Immunotherapy Toxicity
Patients with severe immunotherapy-related toxicities should discontinue immunotherapy, as this does not impair long-term benefit 1. This is a critical point—you can stop for toxicity without compromising survival outcomes.
Duration and Maintenance
- Immunotherapy: up to 2 years in absence of progression or intolerable toxicity 1
- Chemotherapy: up to 6 cycles for non-progressing patients without unacceptable toxicity 2
- Maintenance pemetrexed is NOT recommended 1
- Vinorelbine or gemcitabine switch maintenance may be offered 1
Radiation Therapy
Radiation has limited roles 1:
- Prophylactic chest wall radiotherapy after procedures to prevent tract seeding
- Palliative treatment for pain-related tumor growth
- Potentially as part of adjuvant multimodality treatment in surgical candidates
Common Pitfalls to Avoid
- Do not offer surgery to patients with sarcomatoid histology—this is futile and harmful 1
- Do not delay immunotherapy testing for PD-L1, TMB, or MSI—these have no role in treatment selection 1
- Do not continue maintenance pemetrexed—observation is preferred after initial chemotherapy 1
- Do not withhold immunotherapy from patients who develop severe toxicity—discontinuation doesn't impair long-term benefit 1
- Do not offer EPP as the surgical approach—P/D is preferred when surgery is indicated 1