Treatment of Mesothelioma

How Is Malignant Mesothelioma Treated, And What Is The Goal Of Each Treatment?

Surgery, chemotherapy and radiation are standard for all types of malignant mesothelioma. Treatment is often focused on reducing symptoms (palliative therapy) and giving the patient more time, rather than getting rid of the cancer and going into remission (curative therapy). This is because mortality is high despite treatment; it is often not caught until at an advanced stage; the cancerous cells are often very spread out; and because patients are often too weak for extensive treatment.

Surgery: A palliative and/or curative therapy. It is the only curative therapy, usually used in Stage I (hasn't spread) in a healthy patient. Used to remove the cancer and possibly nearby tissue or a lung. May also be used palliatively for procedures such as draining accumulated fluid that is causing discomfort.

Chemotherapy: Palliative. Can be taken intravenously or intramuscularly, by mouth as a pill or locally injected into affected area.

Radiation: Palliative. Also used after surgery to avoid spreading mesothelioma to the incision site.

Combination therapy: Using surgery, chemotherapy and radiation, it is the most effective, but the most difficult; and in most cases the cancer will still return at some point.

The Contrasting Roles Of Radiation, Surgery, And Chemotherapy In The Treatment Of Malignant Mesothelioma

The use of radiotherapy is quite limited. While it may offer a palliative role, tumor volume and tissue toxicity restrict its usefulness. Surgical procedures, such as those that debulk the tumor mass, are limited by the ability of the patient to undergo radical resection. Like radiation, surgery may also offer palliation; there is little evidence to suggest that either of these modalities have any other significant impact on the course of the disease. The impact of single-agent chemotherapy in mesothelioma treatment is varied. Approximate response rates range anywhere from 0-35% with cisplatin and methotrexate as the most effective drugs. Combination chemotherapy using traditionally available medications does not seem to have any more positive effect than single-agent and is therefore not widely used. However, emerging trials indicate there may be some benefit to therapy with newer agents when combined with platinums.

How Is Radiation Used In The Treatment Of Pleural Mesothelioma?

Due to the sensitivity of adjacent structures in the thorax such as the heart, esophagus, spinal cord and lung, the use of radiation dosing is limited in pleural mesothelioma treatment. However, it does appear to offer palliative treatment to about half of patients. Unfortunately there have been no studies that show that radiation increases long-term survival. Radiation has also been used along with surgery to help prevent seeding following biopsy and chest tube placement. A third way that radiation is being used in mesothelioma treatment is in combination with chemotherapy and surgery. The best outcomes for patients have come with chemo, post-surgery radiation and extra-pleural pneumonectomy. Unfortunately, recurrence is common even with the combined approaches. There has also been work by a Swiss research team using radiation prior to chemo and surgery with some promising results.

Main Radiation Therapy Treatments For Mesothelioma

Post-operatively, curative or palliative, or as a noninvasive palliative treatment plan, radiation therapy, or radiotherapy, may be utilized. High-energy beams or particle-streams penetrate the affected areas. After an extrapleural pneumonectomy, intensity modulated radiation therapy (IMRT) can be used to eradicate remaining disease, inhibit growth, or prevent metastases.

Current treatment mechanisms:

  • External uses an x-ray machine to administer the radiotherapy.
  • Internal involves radioactive substances placed within the body. The radioactive materials are contained within a catheter, needle, seed or wire.
  • To control radiation so that is does not adversely affect nearby tissue, a multi-modality approach may be employed. With IMRT, computer images guide the radiation to a specific cancerous area.
  • Helical Tomotherapy, the newest, uses 3-D images from a CT scanner to determine the tumor/target size and location, and at-risk areas nearby. The computer generates specifics for the patient's position, exact dosage and x-ray machine settings.

Main Surgical Treatments For Mesothelioma

Depending upon the patients age, health and desires, and the cancer's stage, location, and extent/metastases, the following may be possible:

Pleural: When surgery is not considered curative, treating just the symptoms, palliative surgical intervention, is aimed mostly at pleural effusion. To reduce/remove the excessive fluid, one or more of the following may be utilized: chest Tubes, pleurodesis, or pleuroperitoneal shunt. Curative, more radical, approaches are pleurectomy or decortication to remove larger areas of the pleura or most/all of a tumor, and pneumonectomy to excise part or all of a lung. Extrapleural pneumonectomy is the most radical and also removes part of the chest wall, pericardium and diaphragm.

Peritoneal: Cytoreductive surgery for tumor-removal or peritonectomy to remove part of the peritoneum.

Pericardial: If diagnosed early and the tumor(s) is/are small, removal can be considered, but if in close proximity to the heart, it is high-risk.

Innovative Approaches To Treatment Of Mesothelioma

Currently, many experimental mesothelioma treatment modalities are being investigated. This includes, but is not limited to the following: photodynamic therapy, gene therapy, immunotherapy, and multimodality therapy. Photodynamic therapy administers photosensitive drugs into mesothelial cells, followed by addition of laser light which activates the drugs to destroy cancer cells. The premise behind gene therapy is to correct the disease at the DNA level and many varieties of gene therapy are being examined for mesothelioma treatment. The goal of immunotherapy is to improve a person's immune system and its natural ability to ward off development of cancer. In immunotherapy, health cells are removed from the affected patient, and then these cells are exposed to cytokines and antibodies. Once these healthy cells are "enhanced," they are re-deposited into the peritoneum, where they aid in the body's cancer defense. Lastly, multimodality therapy is the combination of any surgery, radiation therapy or chemotherapy to treat mesothelioma.