Mesothelioma Treatment – Chemotherapy

Like radiation, chemotherapy provides no cure for mesothelioma but can go a long way in providing relief from the horrendous symptoms of the disease. As researchers continue to test different combinations of chemotherapy drugs, patients continue to benefit from their findings, and someday, chemo may go a lot further in prolonging the life of a mesothelioma victim.

Chemotherapy is given in pill form or injected. In the case of mesothelioma patients, the drugs are given intrapleurally (into the chest cavity) or intraperitoneally (into the abdominal cavity). Doctors usually combine two drugs for the best result. Currently, the preferred combination is Alimta© (pemetrexed) and Cisplatin, but other drugs are used in tandem if deemed preferable for a specific patient. In some cases, patients can only tolerate a single drug so only one is used for treatment.

Other drugs are given to the patient to combat the unpleasant side effects of chemo, such as medication to relieve nausea and vomiting or vitamins to replace essential ones lost during chemotherapy.

Some patients decide that the side effects of chemotherapy are too severe and opt not to receive this treatment.

Mesothelioma Symptoms

The early symptoms of mesothelioma are generally non-specific, and may lead to a delay in diagnosis. Sometimes resembling viral pneumonia, pleural mesothelioma patients may present with shortness of breath, chest pain and/or persistent cough; some patients show no symptoms at all. A chest x-ray may show a build-up of fluid or pleural effusion (discussed below). The right lung is affected 60% of the time, with involvement of both lungs being seen in approximately 5% of patients at the time of diagnosis. Less common symptoms of pleural mesothelioma include fever, night sweats and weight loss. Symptoms of peritoneal mesothelioma may include pain or swelling in the abdomen due to a build-up of fluid, nausea, weight loss, bowel obstruction, anemia or swelling of the feet.

Pleural Effusion
One of the most common symptoms of mesothelioma is a pleural effusion, or an accumulation of fluid between the parietal pleura (the pleura covering the chest wall and diaphragm) and the visceral pleura (the pleura covering the lungs). Both of these membranes are covered with mesothelial cells which, under normal conditions, produce a small amount of fluid that acts as a lubricant between the chest wall and the lung. Any excess fluid is absorbed by blood and lymph vessels maintaining a balance. When too much fluid forms, the result is an effusion.

Types
Pleural effusion is broken down into two categories, transudates and exudates. A transudate is a clear fluid that forms not because the pleural surfaces are diseased, but because of an imbalance between the normal production and removal of the fluid. The most common cause of transudative fluid is congestive heart failure. An exudate, which is often cloudy and contains many cells and proteins, results from disease of the pleura itself, and is common to mesothelioma. To determine whether a fluid is a transudate or exudate, a diagnostic thoracentesis, in which a needle or catheter is used to obtain a fluid sample, may be conducted.

Symptoms
As the volume of fluid increases, shortness of breath, known as “dyspnea”, and sometimes pain, ranging from mild to stabbing, may occur. Some patients may experience a dry cough. When the doctor listens to the patient’s chest with a stethoscope, normal breath sounds are muted, and tapping on the chest will reveal dull rather than hollow sounds.

Diagnosis
Diagnosis of pleural effusion is usually accomplished with a simple chest x-ray, although CT scans or ultrasound may also be used. A special x-ray technique, called a lateral decubitus film, may be used to detect smaller effusions or to enable the physician to estimate of the amount of fluid present. If the underlying cause of the effusion is readily apparent (such as in the case of severe congestive heart failure), sampling of the fluid may not be necessary, however, because pleural effusion may be symptomatic of a number of disease processes from benign to malignant, a fluid sample is generally taken. Diagnostic thoracentesis, in which cells are extracted from the pleural cavity, is commonly done when the possibility of mesothelioma exists, however, in up to 85% of cases, the fluid tests negative or inconclusive even though cancer is present. It is ultimately a needle biopsy of the pleura (lining of the lung) or an open surgical biopsy which confirms a mesothelioma diagnosis.

Treatment
Pleural effusion caused by heart failure or infection can usually be resolved by directing treatment at the cause, however, when testing has realized no diagnosis, and fluid continues to build or recur, doctors may recommend chest tube drainage and chemical pleurodesis. Chemical pleurodesis is a technique in which a sclerosing agent is used to abrade the pleural surfaces producing an adhesion between the parietal and visceral pleurae. This will prevent further effusion by eliminating the pleural space. Talc appears to be the most effective agent for pleurodesis, with a success rate of nearly 95%. It is highly effective when administered by either poudrage or slurry. Poudrage is the most widely used method of instilling talc into the pleural space. Before spraying the talc, the medical team removes all pleural fluid to completely collapse the lung. After the talc is administered, they inspect the pleural cavity to be sure the talc has been evenly distributed over the pleural surface. Some doctors prefer to use talc mixed with saline solution which forms a wet slurry that can roll around the pleural cavity.

Types of Mesothelioma

Pleural mesothelioma:
Pleural mesothelioma is the most common type of mesothelioma, a rare cancer that develops in the mesothelial cells that make up the mesothelium, a membrane that lines many of the body’s organs and cavities. In the case of pleural mesothelioma, the cancer develops in the lining of the lungs, called the pleura or pleural membrane

The pleura is comprised of two layers which provide support and protection for the lungs and chest cavity. The outer layer, or the parietal layer, lines the entire chest cavity and the diaphragm. The inner layer, or visceral layer, covers the lungs. Pleural mesothelioma typically develops in one layer, but can metastasize, or spread, to the other layer.

Like all mesothelioma cancers, pleural mesothelioma is caused by asbestos exposure and develops when the toxic asbestos fibers become trapped in the spaces between the mesothelial cells.

Peritonial Mesothelioma:
Peritonial mesothelioma is a rare, aggressive cancer caused by asbestos exposure. Of the 2,000 to 3,000 cases of mesothelioma diagnosed in the United States annually, 10 to 20 percent of the patients are diagnosed with peritoneal mesothelioma. Peritoneal mesothelioma develops in the abdomen, in the mesothelial cells that form a membranous layer called the peritoneum.

The peritoneum is a membranous layer that is made up of two ’sub-layers’ called the parietal and visceral layers. The parietal layer covers the abdominal cavity, while the visceral layer surrounds abdominal organs. Together these two layers provide support and protection for abdominal organs and the abdominal cavity as a whole.

Peritoneal mesothelioma, like all types of mesothelioma, is caused by asbestos exposure. Though it can take many years for a patient to demonstrate symptoms of peritoneal mesothelioma, the cancer develops when the asbestos fibers become lodged in the spaces between the mesothelial cells.

Pericardial mesothelioma:
Pericardial mesothelioma accounts for approximately half of all pericardial tumors and is an extremely rare. Researchers from various mesothelioma studies report that pericardial mesothelioma accounts for approximately 1 to 6 percent of all mesotheliomas. To date, fewer than 150 cases have been presented in medical literature and approximately 200 cases have been reported worldwide. Pericardial tumors are typically diffuse (not localized) and tend to cover most of the heart.

Pericardial mesothelioma develops in the pericardium, a membrane made up of mesothelial cells that surrounds the heart and provides protection and support to this organ. The membrane is composed of two different layers: an outer layer called the parietal layer (called the heart sac or theca cordis), and an inner layer known as the visceral layer (called the epicardium). The parietal layer is part of a larger membrane that lines the entire chest cavity, while the visceral layer is the pericardial membrane that lines the heart.

Understanding Mesothelioma?

Mesothelioma is a cancer of the mesothelium. The mesothelium is a thin membrane that lines the chest and abdomen and surrounds the organs in these areas. The lining around the lungs is called the pleura and in the abdomen it is known as the peritoneum.

Tumors of the mesothelium can be benign or they can be cancerous. A cancerous tumor of the mesothelium is called a malignant mesothelioma, but this is often shortened to just mesothelioma. The information that follows covers only those tumors that are cancer.

Main types of mesothelioma

There are 3 main types of mesotheliomas based on how the cells look under a microscope.

• Epithelioid: This is the most common type. It tends to have a better outlook (prognosis) than the other types.
• Sarcomatoid (fibrous): About 1 or 2 out of 10 mesotheliomas are of this type.
• Mixed (biphasic): This type has features of the 2 types above. About 3 or 4 out of 10 mesotheliomas are the mixed type.

About 3 out of 4 mesotheliomas start in the chest cavity. These are called pleural mesotheliomas. Another 10%-20% begin in the abdomen (belly). These are called peritoneal mesotheliomas. Those starting around the heart are very rare. This cancer can also start in the tissue around the testicles, but this is also very rare.