Mesothelioma is an aggressive form of cancer, which means it progresses and spreads rapidly. Malignant mesotheliomas can be classified according to where the cancer develops. The three most common types of malignant mesothelioma are pleural mesothelioma, peritoneal mesothelioma and pericardial mesothelioma.
Pleural malignant mesothelioma – Most people diagnosed with malignant mesothelioma develop cancer in the pleura, lung mucosa and thoracic cavity. This aggressive cancer causes thickening of the pleura, preventing normal expansion of the lungs and chest. As a result, fluid may accumulate in the thoracic cavity.
Peritoneal malignant mesothelioma – This type of cancer develops in the peritoneum, in the thin membrane that surrounds the abdominal cavity and the surface of the abdominal organs. Inhaled asbestos fibers can also reach the peritoneum through the lymphatic system. Occasionally, malignant pleural mesothelioma metastasizes or spreads from the lungs to the abdominal cavity. Pericardial malignant mesothelioma – It is the rarest form of mesothelioma. This affects the protective layer of the heart.
Diagnosis of malignant mesothelioma
Mesothelioma is often diagnosed at a more advanced stage of cancer. The doctor will ask a series of questions regarding the personal and family medical history and will perform a physical examination, to evaluate any potential exposure to asbestos. A physical examination can provide information on possible signs of mesothelioma and aother health problems. Pleural mesothelioma can cause fluid to form around the lungs. In cases of peritoneal mesothelioma, fluid may accumulate in the abdomen (called ascites). In pericardial mesothelioma, the fluid accumulates around the heart. Rarely, mesothelioma can develop in the groin area and look like a hernia. All of these can be found during a physical exam. If this form of cancer is suspected, a series of tests and investigations may be recommended:
Biopsy – A biopsy can confirm the diagnosis. The type of biopsy depends on where the symptoms are present. A small needle is inserted into the abdomen and chest to pick up a fluid or tissue piece (needle aspiration) or a thoracoscopy will be performed (a thoracoscope is inserted through a small incision between the patient’s ribs).
Invasive Diagnostic Techniques –
Laparoscopy allows the surgeon to examine the inside of the abdomen. Using one or more small incisions in the abdomen, the surgeon introduces a small room and special surgical tools to take a small piece of tissue for examination. Thoracotomy is a surgery in which a tissue sample can be taken for testing from the thoracic region by intervention. Laparotomy is a surgery that opens the abdomen to allow a tissue sample to be taken.
Imaging Tests – Imaging tests use X-rays, radioactive particles, sound waves, or magnetic fields to create images inside the body. Radiography is often the first test performed if someone has symptoms such as constant coughing or difficulty breathing. Computed tomography (CT) is often used to help detect mesothelioma and determine the exact location of the cancer and can show if it has spread to other organs. Echocardiography uses sound waves to analyze the heart if it is suspected that you have fluid around the heart. Positron emission tomography(PET) may provide useful information whether the abnormal areas observed on these tests may be cancerous or not, and may identify a thickening of the pleura or peritoneum. Magnetic resonance imaging (MRI) can help to accurately locate a tumor.
Blood tests – Blood levels of certain substances are often higher in people with mesothelioma, namely osteopontin – a soluble peptide linked to mesothelin, another type of specific protein. Also, joint blood tests will be performed, such as a complete blood count.
The stage of a cancer helps determine the severity of the cancer and the best treatment.