Peritoneal mesothelioma is the second-most common type of mesothelioma, occurring in about 20% of cases. This form of mesothelioma is a cancer that occurs in the peritoneum, or the lining of the abdominal cavity. The peritoneum surrounds the internal organs for support and lubrication.
Mesothelioma of the peritoneal lining poses a challenge to diagnose as well as to treat. The first symptoms of malignant peritoneal mesothelioma may not appear for decades after exposure to asbestos. Symptoms may also be easily overlooked and mimic other more common illnesses.
Peritoneal mesothelioma patients may have symptoms that include abdominal swelling or pain, weight loss, nausea, and a buildup of fluid in the abdomen. If you have been exposed to asbestos and experience these symptoms, talk to your doctor about peritoneal mesothelioma. An early diagnosis may allow you to pursue treatment that will improve your prognosis and quality of life as you battle this cancer.
Causes of Peritoneal Mesothelioma
The cause of peritoneal mesothelioma is exposure to asbestos. The most accepted theory for how this cancer develops is that asbestos fibers are ingested by the patient, which allows the fibers to easily enter the abdomen and eventually become lodged in the peritoneum. This leads to inflammation and, eventually, to cancer.
Another theory as to how asbestos reaches the peritoneal membrane is that fibers of asbestos are inhaled and eventually travel to the membrane by way of the lymphatic system, which keeps bodily fluids in balance and infections in check.
Regardless of how asbestos fibers enter the peritoneal membrane, once they are there the body has a very difficult time eliminating them. Due to the nature of the fibers, they become lodged in the membrane, where they cause irritation and inflammation. Over a period of years, they begin to change the dynamics of the healthy mesothelial cells, causing them to grow rapidly and uncontrollably.
This rapid growth of cells causes a thickening of the peritoneum and a consequent buildup of fluid in the peritoneal layers, resulting in discomfort for patients. Eventually this cell growth begins to form tumors.
After the initial asbestos exposure, mesothelioma often does not manifest itself for up to 50 years. Due to the long latency period, this form of cancer is often quite advanced when diagnosed and quickly proves fatal.
At the start of the disease, there are rarely any symptoms of the cancer. The first symptom is typically pain in the abdomen, which can often be mistaken for other conditions and delay a correct diagnosis. Later symptoms include swelling of the abdomen, loss of weight, nausea and vomiting, difficulty breathing, obstruction of the bowels, fever, and hernias.
Symptoms of Peritoneal Mesothelioma
Peritoneal mesothelioma is a rare cancer—only 200 to 400 new cases are diagnosed annually in the United States. Symptoms of this disease include the following:
- Nausea or vomiting
- Inexplicable weight loss
- Sweating or fever
- Swelling or pain in the abdomen
- Ascites (fluid buildup between the peritoneum and the abdominal organs)
- Diarrhea, constipation, or any other inexplicable changes in the bowels
- Development of lumps under the skin on the abdomen
These symptoms usually arise as a result of the thickening of the membrane surrounding the abdomen. This thickening is brought on by rapidly growing cancerous cells. Generally, this rapid growth leads to an accumulation of fluid between the membranes in this area that puts pressure on the abdomen and eventually brings on symptoms of this cancer.
Diagnosing Peritoneal Mesothelioma
To obtain a diagnosis, a physician will conduct physical examinations, review medical histories, and conduct imaging studies such as CT and MRI scans. After finding the location of the tumor, the physician will perform a biopsy to determine whether the tumor is cancerous. Unlike with pleural mesothelioma, there is no current system for determining the stage of this cancer. Instead, most physicians go straight to the treatment options.
Treating the Disease
Peritoneal mesothelioma is typically discovered when the disease is in the advanced stages, due both to its long latency period and to the difficulty in making the diagnosis. Survival time after diagnosis is about a year. For this reason, most treatment for peritoneal mesothelioma focuses on palliative treatments to relieve symptoms and manage pain rather than to effect a cure.
One of the most useful treatment options for this cancer is a combination of two traditional therapies: surgery and chemotherapy. Known as multimodal therapy, the combined treatments relieve symptoms and limit cancer growth more effectively than a single treatment would.
Surgery is often used to remove some or all of a cancerous tumor, depending on the stage of the disease. Surgical procedures for peritoneal mesothelioma include peritonectomy, cytoreductive surgery, and paracentesis. With chemotherapy, drugs are employed to shrink or retard the growth of mesothelioma tumors. Chemotherapy can be given before, during, or following surgery. Chemotherapy drugs for peritoneal mesothelioma include cisplatin, gemcitabine, and pemetrexed, according to the National Institutes for Health. Radiation therapy is rarely recommended as a treatment for peritoneal mesothelioma because it could harm nearby vital organs.
Research studies as well as clinical trials are ongoing to help increase the likelihood of developing a cure for peritoneal mesothelioma. Currently, the best chance of cure is to find the cancer in its very early stages. For this reason, people who have undergone exposure to asbestos should receive frequent checkups to watch for mesothelioma or other asbestos-related conditions and diseases.