Stage is the most important factor in determining a patient's prognosis. Patients diagnosed at an early stage of mesothelioma will have more treatment options and a better prognosis than those diagnosed at a later stage.

While average life expectancy varies for patients diagnosed with each type of mesothelioma, peritoneal (abdomen) patients typically survive one year or longer, and pleural (lung) mesothelioma patients have an average prognosis of about six months to one year.

Epithelioid mesothelioma is the most common cell type and also has the best prognosis. The prognosis worses with biphasic mesothelioma due to the presence of sarcomatoid cells. Sarcomatoid mesothelioma has the least favorable prognosis, as these cells spread aggressively and are not as responsive to cancer treatments.

Mesothelioma metastasis means the cancer has spread beyond where the tumors originated, limiting treatment options and greatly impacting life expectancy. Once the disease begins to spread, it is much harder to remove the cancer through surgery or kill the cancer cells with chemotherapy.

Poor overall health will limit treatment options and lower life expectancy for patients facing a mesothelioma diagnosis. Older patients may not be able to withstand the side effects of surgery, chemotherapy or radiation therapy, and also tend to have other conditions that can worsen the disease or limit treatment options.