Is peritoneal mesothelioma the same as the lung one?

No. Pleural mesothelioma arises in the membrane around the lung, is more common and has a worse prognosis. The peritoneal form arises in the abdominal membrane and, in the epithelioid subtype with a complete cytoreduction, the published results are very different: a median of 53 months in the international registry of 405 patients.

How long do people live with peritoneal mesothelioma?

With systemic treatment alone, historical median survival is six to twelve months. In patients treated with cytoreduction and hyperthermic intraperitoneal chemotherapy, the published median is 53 months, with 47% alive at five years. The gap between those figures is selection and complete surgery, not the drug alone.

Do I need to have been exposed to asbestos?

Not necessarily. Asbestos exposure is a known risk factor for mesothelioma, but many patients with peritoneal disease have no identifiable exposure, and not having one does not rule out the diagnosis.

My biopsy says sarcomatoid. What does that mean?

That the disease behaves more aggressively. Median survival is under twelve months with any treatment and major surgery is generally not indicated. It is the hardest part of this disease and there is no point softening it, because softening it leads to operations that do not help.

Does a high PCI rule me out?

Not on its own. In the registry of 405 patients, PCI was not an independent prognostic factor, unlike subtype and completeness of cytoreduction. What rules surgery out is disease that cannot be removed in full, and that depends on where it sits rather than how much there is.

Peritoneal mesothelioma — subtype, surgery and survival

Peritoneal mesothelioma

A rare tumour that arises in the peritoneum itself. It is not lung mesothelioma, it is not treated the same way, and its prognosis with surgery is very different.

Diffuse malignant peritoneal mesothelioma does not reach the peritoneum from somewhere else: it starts there, in the membrane itself. That sets it apart from peritoneal carcinomatosis, which always comes from a tumour in another organ.

The first thing worth clearing up is the one that causes most confusion. Search for “mesothelioma” and you will mostly find material on pleural mesothelioma, the one in the chest, which is considerably more common, is treated differently and carries a worse prognosis. Pleural trials cannot be used to decide about a peritoneal patient, and the survival figures you read there are not yours.

How it presents

The symptoms are those of an irritated membrane producing more fluid than it reabsorbs, and of something slowly taking up room. Almost none are specific, which is why diagnosis is usually late:

An increase in abdominal girth from fluid accumulation — ascites.
Diffuse, poorly localised abdominal pain.
Early satiety and weight loss.
Sometimes a palpable mass, or a recent hernia that is really the abdominal wall giving way under pressure.

The subtype decides almost everything

In this disease the pathology matters more than the extent.

The epithelioid subtype is the one that responds to surgical treatment and the one behind the good figures. It is also the commonest.

The sarcomatoid subtype is the unfavourable one, and here it is better to be direct: median survival is under twelve months with any treatment, and major surgery is generally not indicated. It is not a matter of finding a surgeon willing to operate — the disease simply behaves differently.

Subtypes and their prognostic weight: Yan TD, et al. Journal of Clinical Oncology, 2009, and the author's material.

What surgery changes

With systemic treatment alone, historical median survival in peritoneal mesothelioma is six to twelve months.

In the multi-institutional registry of 405 patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, the median was 53 months, with 60% of patients alive at three years and 47% at five.

That study identified four independent factors: epithelioid subtype, absence of nodal involvement, achieving a complete cytoreduction, and receiving the intraperitoneal chemotherapy. One is conspicuous by its absence from that list: the PCI. In this disease, unlike others, the total volume of tumour was not an independent factor.

The price is published too: serious complications in 31% of patients and a perioperative mortality of 2%.

Yan TD, Deraco M, Baratti D, et al. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for malignant peritoneal mesothelioma: multi-institutional experience. Journal of Clinical Oncology, 2009 (405 patients). Survival with systemic treatment alone: the author's material.

Who is a candidate

The combination being looked for is epithelioid subtype, disease that can be removed in full, and a general condition that will tolerate a long operation.

On extent, consensus criteria put the usual ceiling below a PCI of 20, with selected patients up to 30. But, as everywhere in peritoneal disease, what really decides is distribution: disease that spares the mobile small bowel can be cleared even when there is a lot of it, and disease infiltrating the mesentery prevents a complete cytoreduction even when there is little.

CT staging falls short for small-volume disease, so the assessment is usually completed with a diagnostic laparoscopy before committing a patient to major surgery.

PCI thresholds by histology as set out in the author's material, drawing on the international consensus documents.

Why pleural mesothelioma cannot be read across

Surgical trials in pleural mesothelioma study a different operation, in a different cavity, in a disease that behaves differently. A negative result there says nothing about peritoneal cytoreduction — and yet it is what will come up first in any search.

If someone has given you a prognosis based on mesothelioma figures without saying which, it is worth asking which mesothelioma they meant.

What this page does not do

The figures describe 405 selected patients operated on in experienced centres. They describe a group, not a person, and the selection is part of the result.

This does not replace a consultation. In peritoneal mesothelioma the decision depends on the biopsy, on the distribution of disease and on your general condition, and all three have to be seen.

Frequently asked questions

What patients ask in clinic

Is peritoneal mesothelioma the same as the lung one?: No. Pleural mesothelioma arises in the membrane around the lung, is more common and has a worse prognosis. The peritoneal form arises in the abdominal membrane and, in the epithelioid subtype with a complete cytoreduction, the published results are very different: a median of 53 months in the international registry of 405 patients.
How long do people live with peritoneal mesothelioma?: With systemic treatment alone, historical median survival is six to twelve months. In patients treated with cytoreduction and hyperthermic intraperitoneal chemotherapy, the published median is 53 months, with 47% alive at five years. The gap between those figures is selection and complete surgery, not the drug alone.
Do I need to have been exposed to asbestos?: Not necessarily. Asbestos exposure is a known risk factor for mesothelioma, but many patients with peritoneal disease have no identifiable exposure, and not having one does not rule out the diagnosis.
My biopsy says sarcomatoid. What does that mean?: That the disease behaves more aggressively. Median survival is under twelve months with any treatment and major surgery is generally not indicated. It is the hardest part of this disease and there is no point softening it, because softening it leads to operations that do not help.
Does a high PCI rule me out?: Not on its own. In the registry of 405 patients, PCI was not an independent prognostic factor, unlike subtype and completeness of cytoreduction. What rules surgery out is disease that cannot be removed in full, and that depends on where it sits rather than how much there is.

Sources

Yan TD, Deraco M, Baratti D, et al. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for malignant peritoneal mesothelioma: multi-institutional experience. Journal of Clinical Oncology, 2009.
International consensus documents on PCI thresholds and indication by histology (PSOGI and the Chicago Consensus), as recorded in the author's monograph.
Lozano Lominchar P, González Bayón L. Margin Clear — Surgical Oncology Board Review. Madrid, 2026.

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