The main factors in estimating the life expectancy of a patient diagnosed with peritoneal mesothelioma are the stage of cancer when it is first detected and the subsequent treatment methods. When the disease is diagnosed in its incipient phase, followed by a multimodal treatment approach (consisting of radiotherapy, chemotherapy, and surgery) or by a combination of standard treatment and alternative options available in clinical trials, life expectancy may be significantly extended. It has been estimated that 25% of patients who receive timely adequate treatment for peritoneal mesothelioma survive for approximately 3 years. However, life expectancy can exceed 3 years in certain cases, as there have been patients surviving up to 5 years after the diagnosis.