Malignant Sarcomatoid Mesothelioma

Malignant mesothelioma is a rare form of cancer in which malignant cancer cells are found in the thin layer of tissue, called the pleura, 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 thin layer of tissue, called the peritoneum, that lines the abdomen and covers most of the organs in the abdomen.

Risk factors 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.

The nucleus of sarcomatoid cells is tougher to detect under an electron microscope than the nuclei of epitheliold mesothelioma cells and sarcomatoid mesothelioma cells can further divide into several other types of cancerous cells called acinar cell, clear cell, small cell, and tubopapillary cell.

Malignant sarcomatoid mesothelioma typically stems from support tissues such as bone, cartilage, fat, and muscle and it is often confused with other types of cancer due to the cells irregular oval shape. It is most often confused with sarcomatoid carcinoma, which is rare in the lungs, as well as sarcoma, pulmonary sarcomatoid carcinoma, and high-grade sarcoma. High-grade sarcoma is a form of cancer found in the body’s supportive tissue including bone, cartilage, fat or muscle.

Malignant sarcomatoid mesothelioma accounts for roughly 10%-15% of all mesothelioma cancer cells making it the least common form of malignant mesothelioma. Other estimates place the percentage at 20%, but unfortunately, this form of malignant mesothelioma is still currently the deadliest. Death usually occurs within six months of diagnosis of malignant sarcomatoid mesothelioma.

Treatments for malignant sarcomatoid mesothelioma, malignant epithelioid mesothelioma, and malignant biphasic mesothelioma are all the same, but it is important to understand that malignant sarcomatoid mesothelioma is the most resistant to treatment. Treatments for malignant mesothelioma include two types: traditional mesothelioma treatments and new mesothelioma treatments. New malignant mesothelioma treatments include gene therapy, immunotherapy, intensity modulated radiation therapy or IMRT, photodynamic therapy or PDT and development of new chemotherapy agents.

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 types of malignant mesothelioma, especially malignant sarcomatoid mesothelioma.

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 sarcomatoid 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.

Because sarcomatoid mesothelioma is often confused sarcomatoid carcinoma, sarcoma, pulmonary sarcomatoid carcinoma, and high-grade sarcoma, it’s best to seek a second opinion – preferably from an oncologist specializing in mesothelioma.

'Malignant Sarcomatoid 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 Treatments Non-traditional Mesothelioma Treatment Options” Resource4 Mesothelioma (online article) 2007
    Accessed: 3/6/08.
  6. “Mesothelioma Treatment Options” (online article) 1/11/07
    Accessed: 3/6/08.