Mesothelioma
- Shamila Habibi
- Jul 8, 2025
- 1 min read
Updated: Dec 4, 2025
Background:
Types:
Pleural mesothelioma (~85%)
Peritoneal mesothelioma (~15%)
Histology:
Epithelioid Mesothelioma:
Epithelioid-to-round cells
Better prognosis
Non-Epithelioid Mesothelioma:
Sarcomatoid: Spindle cells with tapered nuclei
Biphasic: Contains both epithelioid and sarcomatioid components in various proportions (each at least 10% of the tumor)
Diagnosis:
Immunohistochemical panels are essential for diagnosis, requires both criteria:
2 positive mesothelial markers: WT1, calretinin, D2-40
2 negative markers: TTF-1, CEA, claudin-4 (these are typically positive in adenocarcinoma)
Broad molecular profiling to identify rare driver alterations (e.g. ALK or NTRK fusions), for which targeted therapies may be available.
Pleural Mesothelioma
Background:
Predominantly affects males (median age 72) with prior asbestos exposure
Highly aggressive cancer, typically unresectable at diagnosis.
2-year survival rate is 30-40% and 5-year survival rate is ~10%
Treatment:
Surgery:
Consider only for stage I-IIIA disease with epithelioid histology
Systemic therapy:
First line:
Cisplatin + Pemetrexed ± Bevacizumab
Cisplatin + Pemetrexed + Pembrolizumab (IND227 trial)
21% reduction in risk of death compared to chemotherapy alone
Ipilimumab + Nivolumab (Checkmate-743)
Survival benefit is most pronounced in non-epithelioid histology
Second line:
If immunotherapy used in first line: use chemo
If chemo used in first line: use ipi/nivo
Peritoneal Mesothelioma
Background:
Affects males and females equally and occurs in younger patients (age ~60s)
Better overall prognosis compared to pleural mesothelioma.
5-year survival is around 20%
Treatment:
Surgery:
Complete cytoreductive surgery (CRS) + Hyperthermic intraperitoneal chemotherapy (HIPEC)
The goal is macroscopic complete resection of tumor
Often require total parietal peritonectomy with visceral resections as needed.
Systemic therapy:
Regimens are the same as pleural mesothelioma