Malignant Epitheliod Mesothelioma

Malignant mesothelioma is a rare form of cancer. It occurs when malignant cancer cells collect in the pleura – the thin layer of tissue that lines the chest cavity and covers the lungs. Malignant mesothelioma is also a disease in which malignant cancer cells can be found in the peritoneum thin layer of tissue that lines the abdomen and covers most of the organs in the abdomen, called the peritoneum.

Various risk factors exist for malignant mesothelioma and they include: working or living in a place where asbestos is inhaled or swallowed, living with an individual who works near asbestos, and being exposed to a certain virus. The period between the time of exposure to asbestos and the onset of symptoms is estimated at 20 to 50 years, which is why most cases are diagnosed later in life. Signs of malignant mesothelioma include trouble breathing, weight loss, lumps in the abdomen, pain under the rib cage, and pain or swelling in the abdomen.

Out of the thousands of people who are diagnosed with malignant mesothelioma each year, the vast majority are men. Malignant mesothelioma is diagnosed through physical examination, chest x-ray, complete blood count (CBC), sedimentation rate, bronchoscopy, cytologic exam, or biopsy such as fine needle aspiration biopsy (FNA), thoracoscopy, laparotomy, or thoracotomy.

Malignant mesothelioma is divided into three types or “histological categories” including epithelioid mesothelioma, biphasic mesothelioma, and sarcomatoid mesothelioma. Malignant mesothelioma types are further divided into subtypes under each category. In many cases, malignant mesothelioma patients will have more than one type of cell.

Epithelioid mesothelioma accounts for roughly 50%-70% of all malignant mesothelioma cases. It is the most common cell type, exhibiting a uniform shape and tubular pattern along with a unique cell nucleus. Epithelioid cells are shaped like cubes. Epithelioid mesothelioma occurs in the mesothelium, a protective layer of tissue called an epithelium that surrounds certain organs such as the lungs and gastrointestinal tract.  Symptoms of this type of malignant mesothelioma include chest pain, fluid build-up or pleural effusions, and respiratory difficulty. It is important to note that epithelioid mesothelioma is often confused with adenocarcinoma. It is recommended that individual’s diagnosed with adenocarcinoma seek a second opinion.

Treatment options for malignant epithelioid mesothelioma as well as malignant sarcomatoid mesothelioma and malignant biphasic mesothelioma are all the same. Some treatments may be used alone or in combination with one another. Treatments for malignant mesothelioma will fall under two main categories. These include traditional mesothelioma treatments and new mesothelioma treatments.

Traditional mesothelioma treatments include: surgery, chemotherapy, and radiation therapy or radiotherapy. In many cases a trimodality approach is employed, which means several treatments are combined for the very best outcomes, for a better chance at long-term survival, and/or a better quality of life. The type of treatment will also vary depending on the stage of the malignant mesothelioma. There are four stages.

Types of malignant mesothelioma surgery include pleurectomy/decortication, pneumonectomy, thoracentesis, and the most drastic type of surgery -- extrapleural pneumonectomy. Pleurectomy/decortication removes part of the infected lung and the surrounding chest lining; pneumonectomy involves total lung removal, and thoracentesis is a type of surgery that involves the draining of excess fluid from the lungs through a needle. This procedure aids in breathing and reduces stress and pressure on the lungs.  Pleurectomy/decortication and pneumonectomy are mostly performed to relieve pain and they rarely have an effect on the survival rate of patients.

Extrapleural pneumonectomy is typically performed in the earliest stages of malignant mesothelioma. It is a complicated procedure that involves the total removal of the linings that surround the lung, heart, and diaphragm. This will prevent the lining from being infected with mesothelioma. This procedure is performed on relatively healthy patients and in combination with chemotherapy and radiation. It typically takes a year to recover. While extrapleural pneumonectomy will extend life by several years, it is not a cure for any of the three types of malignant mesothelioma.

Radiation therapies for the three types of malignant mesothelioma include two main types: internal radiation therapy also known as brachytherapy and external radiation therapy. Radiation is used to kill cancer cells and shrink the tumor to a manageable size. It relieves pain and reduces symptoms such as shortness of breath. Radiation does not, however, come without consequences. In order to kill all of the cancerous cells, there can be significant damage to the patient.

Chemotherapy involves several types of anti-cancer drugs either injected directly into the lungs or taken in pill form or intravenously. Chemotherapy drugs disrupt the growth of cancer cells in patients with malignant mesothelioma. Unfortunately, these drugs can damage normal healthy cells as well and can cause unpleasant side effects ranging from hair loss and nausea to anemia and hemorrhaging. Additionally, chemotherapy is not very effective in treating the three types of malignant mesothelioma, especially sarcomatoid mesothelioma.

New malignant mesothelioma treatments include gene therapy, immunotherapy, intensity modulated radiation therapy or IMRT, photodynamic therapy or PDT and development of new chemotherapy agents. New mesothelioma treatments such as gene therapy, immunotherapy, and photodynamic therapy or PDT offer new hope for doctors and mesothelioma patients. Doctors, scientists, and researchers are attempting to further develop these new treatment modalities, with the hope that they will be successful where traditional treatments have failed. To date, these new treatments for mesothelioma have not quite measured up to traditional methods, but they are currently being used in conjunction with traditional methods and they are, of course, constantly being monitored and assessed.

In addition to new malignant mesothelioma treatments such as gene therapy, immunotherapy, intensity modulated radiation therapy or IMRT, photodynamic therapy or PDT, and the development of new chemotherapy agents, there are other “radical forms” of treatment for malignant epithelioid mesothelioma, such as angiogenesis therapies, antineoplaston therapy, mesothelioma clinical trials, interferon and interleukin therapy, and radiofrequency ablation. A wide variety of complementary and alternative mesothelioma treatments are also currently being explored including: herbal products, special diets, homeopathic medicine, acupuncture, therapeutic massage, high dose vitamin C, laetrile (amygdalin, extracted from fruit pits), and Eastern medicines.

'Malignant Epitheliod Mesothelioma' Resources:
  1. “Epithelioid, Sarcomatoid and Biphasic Mesothelioma Cancer Cell Types” (online article) 2005
    Accessed: 3/6/08.
  2. “Mesothelioma Questions and Answers” (online fact sheet) 5/13/2002
    Accessed: 3/6/08.
  3. “Types of Complementary and Alternative Medicine (CAM)” (online article) 6/8/05
    Accessed: 3/6/05.
  4. “Types of Mesothelioma” (online article) 1/11/07
    Accessed: 3/6/08.
  5. “Mesothelioma Treatment Options” (online article) 1/11/07
    Accessed: 3/6/08.