Peritoneal mesothelioma is a less common form of the disease than pleural mesothelioma, and consequently it is not very well understood. It has not been definitively shown that the two forms of the disease are similar, even though they share the same primary risk factor-asbestos exposure. Research has found that these two types of malignant mesothelioma have two different gene profiles, which suggests that their origins and development are different from one another.
Who is affected?
According to the Mesothelioma Research Foundation of America, there are approximately 2 to 2.6 new cases per million in the United States each year.
Unlike pleural mesothelioma, this mesothelioma is found more often in women than in men and mesothelioma symptoms appear at a younger age.
In a study titled Malignant abdominal mesothelioma: defining the role of surgery, published January 2009 in the Journal of Surgical Oncology, researchers used the Surveillance, Epidemiology, and End Results (SEER) database between 1973 to 2005 to identify 10,589 cases of malignant mesothelioma. Of these, 9,211 cases were pleural mesothelioma and 1,112 cases were this mesothelioma.
They observed that patients had more localized disease than those patients with peritoneal mesothelioma. However, this mesothelioma more often affected younger patients (63 years vs. 71 years). The average overall survival rate for peritoneal mesothelioma was 13 months for women as compared with six months for men. Patients who underwent surgery had a an average survival time of 20 months as compared to four months for those who didn’t. Surgical patients also had a 28 percent 5-year survival rate as compared with 12 percent for those who didn’t.
What are the Symptoms?
The two subtypes of this mesothelioma are diffuse and localized, with diffuse being more common.
In diffuse peritoneal mesothelioma, the tumor has spread within the abdominal cavity. The typical symptoms include a distended abdomen and/or an increase in abdominal girth, pain, nausea, and weight loss. The patient can also experience bowel obstruction, a sign that the disease is in an advanced stage.
Of all of these symptoms, the distended abdomen is the first to appear. It can result in a feeling of fullness regardless of how little the patient eats, difficulty swallowing, and shortness of breath, which lead to weight loss and lack of energy. Distended abdomens are sometimes misdiagnosed as abdominal wall hernias, and it isn’t until surgery to repair the hernia is initiated that mesothelioma is diagnosed.
The second most common mesothelioma symptom is pain. However, in most instances the pain is widespread and nonspecific, making it difficult to associate it with peritoneal mesothelioma. There are some instances in which the pain is the result of a bowel perforation or obstruction.
Localized, which is less common, presents as a mass with defined borders usually centered in one location, but it can sometimes extend into nearby organs. However, it does not spread throughout the abdominal cavity as in the diffuse subtype. The symptoms are localized abdominal pain, or a mass within the abdomen or pelvis that can be felt during examination.