What Is Peritoneal Mesothelioma?
Peritoneal mesothelioma is a cancer of the peritoneum, the thin membrane lining the abdominal cavity and covering the abdominal organs. It accounts for 10-20% of all mesothelioma diagnoses, making it the second most common form after pleural mesothelioma.
Unlike pleural mesothelioma, peritoneal mesothelioma has a significantly better prognosis. With specialized surgical treatment, 5-year survival rates reach 47-52%, compared to just 12-15% for pleural mesothelioma.
How Peritoneal Mesothelioma Develops
Asbestos Exposure
Like all mesothelioma types, peritoneal mesothelioma is caused by asbestos exposure. The exact mechanism of how asbestos fibers reach the peritoneum isn’t fully understood, but two pathways are proposed:
Risk Factors
| Risk Factor | Details |
|---|---|
| Occupational asbestos exposure | Construction, shipyard, and industrial workers |
| Secondary exposure | Family members of asbestos workers |
| Environmental exposure | Living near asbestos mines or processing facilities |
| Gender | Unlike pleural, affects men and women more equally |
| Genetic factors | BAP1 gene mutations may increase susceptibility |
Symptoms of Peritoneal Mesothelioma
Symptoms develop gradually and are often mistaken for other abdominal conditions.
Early Symptoms
Advanced Symptoms
- Severe abdominal distension
- Bowel obstruction
- Difficulty eating
- Fatigue and weakness
- Night sweats
- Fever
- Anemia
Ascites: The Hallmark Symptom
Ascites — fluid buildup in the abdominal cavity — is the most characteristic symptom of peritoneal mesothelioma. It causes visible abdominal swelling, feeling of fullness, difficulty breathing (when fluid presses on diaphragm), and discomfort when sitting or lying down. Ascites often prompts patients to seek medical attention and leads to diagnosis.
Diagnosis
Diagnostic Process
- Medical history — Including detailed occupational and exposure history
- Physical examination — Checking for abdominal swelling and tenderness
- Imaging tests — CT scan, MRI, PET scan
- Paracentesis — Removing and analyzing abdominal fluid
- Biopsy — Laparoscopy or laparotomy for tissue sample
- Immunohistochemistry — Distinguishes mesothelioma from other abdominal cancers
Cell Types
| Cell Type | Frequency | Prognosis |
|---|---|---|
| Epithelioid | 75% | Best |
| Sarcomatoid | 10% | Poorest |
| Biphasic | 15% | Intermediate |
Peritoneal mesothelioma has a higher percentage of epithelioid cases than pleural, which partly explains better outcomes.
Staging: Peritoneal Cancer Index (PCI)
Peritoneal mesothelioma doesn’t use the standard TNM staging system. Instead, doctors use the Peritoneal Cancer Index (PCI):
Treatment Options
Cytoreductive Surgery with HIPEC
Cytoreductive surgery (CRS) combined with HIPEC (Hyperthermic Intraperitoneal Chemotherapy) is the gold standard treatment for peritoneal mesothelioma and offers the best survival outcomes.
How it works:
- Cytoreductive surgery — Surgeon removes all visible tumors from the abdominal cavity, including affected portions of the peritoneum and sometimes parts of organs
- HIPEC — Heated chemotherapy (104-109°F) is circulated directly in the abdomen for 60-90 minutes, killing microscopic cancer cells surgery couldn’t remove
Who Qualifies for CRS/HIPEC?
| Factor | Effect | Why It Matters |
|---|---|---|
| Lower PCI score | Improves candidacy | Less tumor burden |
| Epithelioid cell type | Improves candidacy | Better response to treatment |
| Good overall health | Improves candidacy | Better tolerance of surgery |
| No distant metastasis | Improves candidacy | Surgery can remove all disease |
| Younger age | Improves candidacy | Better recovery |
| Experienced center | Improves candidacy | Better surgical outcomes |
Chemotherapy
For patients who cannot undergo surgery, systemic chemotherapy is the primary treatment:
Chemotherapy may be used:
- As primary treatment when surgery isn’t possible
- Before surgery (neoadjuvant) to improve surgical outcomes
- Can shrink tumors and relieve symptoms
Immunotherapy
Immunotherapy is emerging as a treatment option for peritoneal mesothelioma:
Palliative Care
For advanced cases, palliative treatments focus on quality of life:
- Paracentesis — Draining ascites fluid for comfort
- Pain management
- Nutritional support
- Symptom control
Survival Rates and Prognosis
| Treatment | Median Survival | 5-Year Survival |
|---|---|---|
| CRS + HIPEC | 53-92 months | 47-52% |
| Chemotherapy alone | 12-14 months | ~10% |
| No treatment | 6-8 months | <5% |
Factors Affecting Prognosis
| Prognostic Factor | Effect |
|---|---|
| Epithelioid cell type | Positive |
| Lower PCI score | Positive |
| Complete cytoreduction achieved | Positive |
| Treatment at high-volume HIPEC center | Positive |
| Good performance status | Positive |
| Female gender | Positive |
| Younger age | Positive |
| No lymph node involvement | Positive |
| Sarcomatoid or biphasic cell type | Negative |
| High PCI score | Negative |
| Incomplete cytoreduction | Negative |
| Lymph node metastasis | Negative |
Finding Specialized Treatment
HIPEC Centers
CRS/HIPEC is a complex procedure that should only be performed at experienced centers. Volume matters — centers performing more procedures have better outcomes.
Am I a candidate for CRS/HIPEC surgery?▼
Candidacy depends on PCI score, cell type (epithelioid preferred), overall health, and absence of distant metastasis. Evaluation at an experienced HIPEC center is essential—center volume matters significantly for outcomes.
What is my PCI score?▼
The Peritoneal Cancer Index scores tumor burden across 13 abdominal regions (0-39 total). Lower scores indicate better surgical candidacy: PCI 0-20 has 103-month median survival vs 33 months for PCI 21-39.
How many HIPEC procedures has this center performed?▼
Volume matters. Look for high-volume centers with experienced surgical oncology teams. Centers performing more procedures have better outcomes and lower complication rates.
Are there clinical trials I might qualify for?▼
Yes, trials studying new immunotherapy combinations, targeted therapies, and novel drug delivery methods are enrolling. Ask your oncologist about trials you may qualify for at major mesothelioma centers.
Living with Peritoneal Mesothelioma
After HIPEC Surgery
| Aspect | What to Expect |
|---|---|
| Hospital stay | 1-2 weeks |
| Full recovery | 2-3 months |
| Dietary changes | May need modified diet initially |
| Follow-up | Regular imaging and check-ups |
Managing Symptoms
- Ascites management — May require periodic drainage
- Nutrition — Work with dietitian for optimal nutrition
- Pain control — Various options from medications to nerve blocks
- Emotional support — Counseling, support groups
Clinical Trials
Patients should ask about clinical trials, which may offer access to:
- New immunotherapy combinations
- Targeted therapies
- Novel drug delivery methods
- Combination approaches