Peritoneal Mesothelioma
Many of the organs in the abdomen are enveloped by a thin membrane of mesothelial cells, known as the peritoneum. When a tumour develops in this membrane it is known as peritoneal mesothelioma. Peritoneal mesotheliomas account for about one-fifth of all mesotheliomas.
The only known cause of peritoneal mesothelioma is previous exposure to asbestos. It is not certain how the asbestos fibres become lodged in the peritoneum. One explanation is that fibres caught by the mucus of the trachea and bronchi end up being swallowed, where some of them lodge in the intestinal tract and from there they can move through the intestinal wall into the peritoneum.
The second explanation is that fibres that lodge in the lungs can move into the lymphatic system and be transported to the peritoneum. Once lodged in the peritoneum the asbestos fibres can act as a carcinogen like asbestos, causing the cells to become cancerous.
Like pleural mesothelioma, peritoneal mesothelioma can be either benign or malignant. The details below apply to malignant peritoneal mesothelioma only.
The Symptoms of Peritoneal Mesothelioma
It can be many years after exposure to asbestos before the disease appears. This disease may not initially show any symptoms, and is sometimes only discovered following a routine abdominal x-ray for a check-up or before surgery.
When the symptoms of peritoneal mesothelioma appear, they can include abdominal pains, abdominal swelling, weakness, weight loss, loss of appetite and nausea. Fluid often accumulates in the peritoneal space, a condition known as ascites.
Over time, the wasting symptoms can become more severe. As the tumour grows, it can exert increasing pressure on the organs in the abdomen, leading to bowel obstruction and other problems. Breathing capacity can be impaired if the tumour presses upward. If the tumour pushes against areas with many nerve fibres, and the bowel distends, the amount of pain can increase.
Diagnosis and Treatment of Peritoneal Mesothelioma
X-rays and CT scans are usually the first step towards detecting peritoneal mesothelioma. Certain diagnosis involves analysis of a piece of the affected tissue. A medical procedure known as a peritoneoscopy is undertaken under anaesthetic to see whether there is any abnormality. If an abnormality is seen, a tissue sample is taken by a biopsy. The tissue sample is then sent for examination by a pathologist who makes a diagnosis using microscopic analysis.
As of yet, there is no known cure for peritoneal mesothelioma. However clinical trials of new drugs and various experimental treatments like gene therapy and immunotherapy, and antiangiogenesis drugs are being undertaken.
The prognosis depends on various factors, including the size and stage of the tumour, its extent, the cell type, and whether or not the tumour responds to treatment.
Treatment is available for pain relief and to reduce symptoms. Many people receive a combination of therapies such as chemotherapy and other drug-based therapies, radiation therapy and surgery.