Patients with a pleural mesothelioma may present with a variety of complaints such as shortness of breath, fever, or chest wall pain. They may also be asymptomatic. Depending on the progression of the disease your assessment may reveal clubbing or pre-clubbing of the fingers, decreased breath sounds on the effected side, or maybe a pleural rub.
Pericardial mesothelioma may present with fever, mid-sternal chest wall pain, shortness of breath, generalized fatigue or other cardiac symptoms caused by fluid compressing the heart. Cardiac tamponade can result and be fatal if not treated in a timely manner. Assessment of vital signs is important paying special attention to the pulse for tachycardia and listening for a paradoxical pulse when taking the blood pressure. Cardiac auscultation may reveal decreased heart tones or a pericardial rub. EKG may reveal pulses alternans.
Peritoneal mesotheliomas can present with fever, abdominal swelling, and various GI complaints but males can also present with scrotal pain.
A mesothelioma is a benign or malignant tumor found in either
the chest (75% are pleural, 2-3% pericardial) or abdomen (20% peritoneal, 1% scrotal). The word comes from “meso” (middle) and “epithelium” (covering/lining). Tumors develop when cells of the mesothelium (the middle layer of cells of the tissue) proliferate to cause abnormal thickening of the sack-like tissues found in the pleural, pericardial and peritoneal cavities.
There are 3 types of mesothelioma based on anatomical location (pleural, pericardial and peritoneal) and 3 sub-types of malignant mesotheliomas based on cell morphology (60% are epitheloid, 20% are sarcomatoid and about 25% are mixed). Sarcomatoid has the worst prognosis while epitheloid carries the best results.
Mesotheliomas are often discovered by finding excess fluid in the chest (chest x-ray), around the heart (echocardiography) and in the abdomen (ultrasound). Ultimately diagnosis comes from examination of mesothelial cells under the microscope. Treatment and prognosis are based on the type, sub-type and stage of the illness.
Chemotherapy, radiation therapy, and surgery are the treatment choices for mesothelioma.
Chemotherapy is a palliative therapy only. The treatment of choice is pemetrexed (Alimta®) combined with cisplatin, but there are several other drug combinations that are also used.
Radiation alone has not been shown to be curative; mesothelioma cells are largely resistant to the effects of radiation. Radiation may be used in conjunction with surgical interventions or employed as a palliative measure alone.
Palliative surgery is used in cases where the patient is too ill to withstand more aggressive surgical options or when the tumor has metastasized. Palliative measures include pleurodesis, decortication, thoracentesis, and paracentesis. Curative surgery is chosen in patients in relatively good health and in cases where the tumor has not invaded other tissues. This includes extensive pneumonectomy, which although not actually curative, has been shown to improve survival by 2-5 years.
Mesothelioma is a difficult cancer to treat. Because it does not grow as a single tumor, it is almost impossible to completely remove. This is true even with a combination of radiation and surgery.
Surgery can be performed to relieve some of the hyperesthesia caused by the tumor, or in attempt to cure the cancer. Curative surgery can only be performed if the tumor is localized and full removal is possible.
If surgery is not appropriate, a procedure called a thoracentesis may be performed to remove excess fluid build up from the thoracic cavity, or abdominal cavity. The procedure is performed by placing a needle into the affected cavity. Occasionally a substance that causes scarring will be injected into the cavity to prevent the fluid build up from returning. While this can make the patient more comfortable, it will not cure the cancer.
Chemotherapy is another treatment that is used to bring palliative relief to patients with mesothelioma. Chemotherapy will not cure mesothelioma.
The prognosis for someone with mesothelioma is quite poor. Typically, at the time of diagnosis the disease is in advanced stages and survival time from that point rarely extends past one year, with life expectancy from the time of diagnosis averaging between 4 and 8 months. Some studies have shown only a 10% survival rate at 3 years and 5% survival rate at 5 years.
The epithelioid type has been shown to have a slightly better prognosis; those with Stage I disease also have a slightly better prognosis. Younger age at the time of diagnosis, diagnosis early in the course of disease leads to a better prognosis, and aggressive treatment all improve prognosis.
The early symptoms of mesothelioma resemble common, minor illnesses. Symptoms of mesothelioma generally appear 2 to 3 months before a diagnosis is made. In about 25% of cases, symptoms may have appeared for six months before a diagnosis is made.
In 50% of patients, pleural mesothelioma presents with hyperesthesia in the low back and at the side of the thorax. The hyperesthesia may be accompanied with difficult respiration. Patients may also report difficulty while swallowing, coughing, elevated temperature, tiredness and loss of weight.
Peritoneal mesothelioma presents with abdominal hyperesthesia, vomiting, nausea and loss of weight.
If a patient exhibits the symptoms of mesothelioma, and also has the risk factors, imaging test will be performed to determine the diagnosis.
An x-ray is generally the first test performed as it will show an irregularity which would suggest the presence of a mesothelioma. If a mesothelioma is suspected, either a computed tomography (CT) scan, or a magnetic resonance imaging (MRI) scan will be performed to establish the size, extent, and location of the mesothelioma.
In conjunction with patient history, definitive diagnosis is made only by biopsy (or autopsy). Specimens are analyzed with various immunohistologic stains as well as examination under electron microscopy.
Mesothelioma is generally divided into 3 histological subgroups: epithelioid, sarcomatoid, and biphasic. Approximately 70% of all mesothelioma is of the epithelioid cell type isolated, which is also the most likely form to be confused with adenocarcinoma. The second most common type is the biphasic form, accounting for about 20-40% of all cases, and made up of a combination of both epithelioid and sarcomatoid cell types. Sarcomatoid mesothelioma is the least common form of the disease, comprising about 15% of all cases, and is most likely to be confused with sarcoma cells.
Exposure to asbestos is the leading risk factor for developing mesothelioma. The use of asbestos in manufacturing stopped after 1989 once asbestos had been linked to mesothelioma. Up until this time, asbestos had been used in products such as, soundproofing, insulation, patching compounds, ironing board covers and roofing.
Asbestos is a naturally occurring fibrous mineral made of silicate. The two main forms of asbestos are amphiboles (thin, rod-like fibers), and serpentine (pliable and coiled). When asbestos is inhaled it is expelled by first sticking to the mucus in the bronchi, and then being coughed up. While the serpentine fibers are easily cleared, the amphiboles are not easily coughed up. The amphiboles can reach the end of the alveoli and penetrate into the surface lining of the pleura.
The risk of developing a mesothelioma is directly related to how long and how much asbestos the person was exposed to. A mesothelioma may take as many as 20 to 50 years to develop.
Although patients can be completely asymptomatic at the time of diagnosis, more often there are vague, non-specific complaints. The rapid proliferation of malignant cells causes pleural effusions in pleural mesothelioma. These effusions can result in dyspnea, hemoptysis, persistent cough, hoarseness, lower back pain, and chest pain. Abdominal mesothelioma is accompanied by ascites and symptoms include bowel obstruction, weight loss, anemia, lower back pain, abdominal pain, edema, fatigue, and fever. Many of these same symptoms may also be seen in pericardial manifestations of the disease.
Patients may complain of their symptoms for 2-6 months before a diagnosis of mesothelioma is made. Imaging studies may reveal the presence of fluid accumulation and tumor, but definitive diagnosis is made only by biopsy or autopsy.
The T stage of malignant mesothelioma is categorized as follows:
T1: Mesothelioma involving either side of pleura lining of the thorax. The mesothelioma is confined to the pleura lining of the lung, and possibly a few additional spots.
T2: Mesothelioma involving either side of pleura lining of the thorax which has also spread from the pleura into the diaphragm, the outer lining of the lung, or the lung itself.
T3: Mesothelioma involving either side of pleura lining of the thorax which has also spread into the first layer of the thorax, the adipose layer of the mediastinum, any single location in the thoracic cavity, or the pericardium.
T4: Mesothelioma involving either side of pleura lining of the thorax which has also spread into the thoracic wall, any organ located within the mediastinum, the spine, through the diaphragm, crossed the pleura through to the other side of the thorax, through the pericardium, the heart, or the brachial plexus.