SIGNS AND SYMPTOMS

Symptoms of mesothelioma may not appear until 20 to 50 years after exposure to asbestos. Shortness of breath, cough, and pain in the chest due to an accumulation of fluid in the pleural space are often symptoms of pleural mesothelioma.

Symptoms of peritoneal mesothelioma include weight loss and cachexia, abdominal swelling and pain due to ascites (a buildup of fluid in the abdominal cavity). Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.

These symptoms may be caused by mesothelioma or by other, less serious conditions.

Mesothelioma that affects the pleura can cause these signs and symptoms:

• chest wall pain
• pleural effusion, or fluid surrounding the lung
• shortness of breath
• fatigue or anemia
• wheezing, hoarseness, or cough
• blood in the sputum (fluid) coughed up

In severe cases, the person may have many tumor masses. The individual may develop a pneumothorax, or collapse of the lung. The disease may metastasize, or spread, to other parts of the body.

Tumors that affect the abdominal cavity often do not cause symptoms until they are at a late stage.

Symptoms include:

• abdominal pain
• ascites, or an abnormal buildup of fluid in the abdomen
• a mass in the abdomen
• problems with bowel function
• weight loss

In severe cases of the disease, the following signs and symptoms may be present:

• blood clots in the veins, which may cause thrombophlebitis
• disseminated intravascular coagulation, a disorder causing severe bleeding in many body organs
• jaundice, or yellowing of the eyes and skin
• low blood sugar level
• pleural effusion
• pulmonary emboli, or blood clots in the arteries of the lungs
• severe ascites

A mesothelioma does not usually spread to the bone, brain, or adrenal glands. Pleural tumors are usually found only on one side of the lungs.

 

Treatment

Treatment of MM using conventional therapies has not proved successful and patients have a median survival time of 6 - 12 months after presentation. The clinical behaviour of the malignancy is affected by several factors including the continuous mesothelial surface of the pleural cavity which favours local metastasis via exfoliated cells, invasion to underlying tissue and other organs within the pleural cavity, and the extremely long latency period between asbestos exposure and development of the disease.

Surgery

Surgery, either by itself or used in combination with pre- and post-operative adjuvant therapies has proved disappointing. A pleurectomy/decortication is the most common surgery, in which the lining of the chest is removed. Less common is an extrapleural pneumonectomy (EPP), in which the lung, lining of the inside of the chest, the hemi-diaphragm and the pericardium are removed. It is not possible to remove the entire mesothelium without killing the patient.

Radiation

For patients with localized disease, and who can tolerate a radical surgery, radiation is often given post-operatively as a consolidative treatment. The entire hemi-thorax is treated with radiation therapy, often given simultaneously with chemotherapy. This approach of using surgery followed by radiation with chemotherapy has been pioneered by the thoracic oncology team at Brigham & Women's Hospital in Boston. Delivering radiation and chemotherapy after a radical surgery has led to extended life expectancy in selected patient populations with some patients surviving more than 5 years. As part of a curative approach to mesothelioma, radiotherapy is also commonly applied to the sites of chest drain insertion, in order to prevent growth of the tumor along the track in the chest wall.

Although mesothelioma is generally resistant to curative treatment with radiotherapy alone, palliative treatment regimens are sometimes used to relieve symptoms arising from tumor growth, such as obstruction of a major blood vessel. Radiation therapy when given alone with curative intent has never been shown to improve survival from mesothelioma. The necessary radiation dose to treat mesothelioma that has not been surgically removed would be very toxic.

Chemotherapy

In February 2004, the United States Food and Drug Administration approved pemetrexed (brand name Alimta) for treatment of malignant pleural mesothelioma. Pemetrexed is given in combination with cisplatin. Folic acid is also used to reduce the side-effects of pemetrexed.

 

Immunotherapy

Treatment regimens involving immunotherapy have yielded variable results. For example, intrapleural inoculation of Bacillus Calmette-Guérin (BCG) in an attempt to boost the immune response, was found to be of no benefit to the patient (while it may benefit patients with bladder cancer). Mesothelioma cells proved susceptible to in vitro lysis by LAK cells following activation by interleukin-2 (IL-2), but patients undergoing this particular therapy experienced major side effects. Indeed, this trial was suspended in view of the unacceptably high levels of IL-2 toxicity and the severity of side effects such as fever and cachexia. Nonetheless, other trials involving interferon alpha have proved more encouraging with 20% of patients experiencing a greater than 50% reduction in tumor mass combined with minimal side effects.

 

Heated Intraoperative Intraperitoneal Chemotherapy

A procedure known as heated intraoperative intraperitoneal chemotherapy was developed by Paul Sugarbaker at the Washington Cancer Institute.The surgeon removes as much of the tumor as possible followed by the direct administration of a chemotherapy agent, heated to between 40 and 48°C, in the abdomen. The fluid is perfused for 60 to 120 minutes and then drained.

This technique permits the administration of high concentrations of selected drugs into the abdominal and pelvic surfaces. Heating the chemotherapy treatment increases the penetration of the drugs into tissues. Also, heating itself damages the malignant cells more than the normal cells.