Through the use of clinical trials that specifically study mesothelioma patients, in addition to the advances made by cancer researchers, experimental therapies are begin developed that may assist in providing new therapeutic options to mesothelioma patients. In addition to surgery, chemotherapy and radiation, there are other options available that are still being tested for safety and effectiveness. Below is a description of some of these newer areas:
Immunotherapy is a form of biologic therapy or biotherapy. It is a form of treatment that may be used as an alternative treatment to radiation therapy or chemotherapy. Immunotherapy utilizes certain parts of the immune system which was built to fight off diseases, including cancer. Medical professionals are harnessing this natural system to aid in the body’s fight against cancer. The way in which this is done is that there is evidence that in many cancer patients the immune system slows down the growth and spread of tumors. The goal of immunotherapy is to harness and enhance the body’s natural tendency to defend itself against malignant tumors. It can do this in two ways:
* Stimulate your own immune system to work harder or smarter to fight against the cancer
* Give you immune system components, such as man-made immune system proteins that assist in the fight against cancer
Immunotherapy is sometimes used by itself to treat cancer, but it is most often used along with or after another type of treatment to boost its effects. Gene therapy and virotherapy are some of the newer approaches used to treat malignant pleural mesothelioma, and their effectiveness is still up to debate.
In virotherapy, the activation of certain oncolytic viruses, are utlitzed and may have the potential to fight mesothelioma cancer. This lies in their ability to specifically target cancer cells without harming healthy cells. “The viruses that we use have a preferential tropism for cancer cells over normal cells. That is, they replicate in mesothelioma cells much more potently than they do in normal cells, explains lead author Richard Vile, PhD, Professor of Immunology and Richard M. Schulze Family Foundation Professor at the Mayo Clinic.
Gene Therapy is the insertion of genes into an individual’s cells and tissues to treat a disease, such as a hereditary disease in which a deleterious mutant allele is replaced with a functional one.
Immunotherapies involving certain cytokines and antibodies have become part of standard cancer treatment and have only recently been used in the treatment of mesothelioma
Newer treatments are now being tested that seem to work better, and will have a greater impact on the outlook for people with cancer in the future.
Cytokines: Interferons (IFN) and Interleukins (IL)
Malignant mesothelioma (MM) is a tumor that is resistant to conventional therapy. Because of its resistance to what some may consider conventional therapies such as radiatation therapy and chemotherapy, researchers are developing new ways to fight this type of mesothelioma cancer.
Interferons are part of a group of proteins known as cytokines. Cytokines are produced naturally by white blood cells in the body in response to infection, inflammation, or stimulation. Interferon-alpha (IFN-alpha) has been used in the treatment of some human tumors, and has demonstrated an in vitro anti-proliferative effect of IFN against MM cell lines.
In 1976, Dr. Robert Gallo isolated a cytokine protein molecule called interleukin (IL2). Interleukin is a biological response modifier (substance that can improve the body’s natural response to infection and disease) that helps the immune system to fight infection and cancer. This protein is capable of stimulating the growth of immune system cells called cells. Interferons are known as natural cell killers, meaning that within healthy individuals, cells search out malignant or virally infected cells and kill them. Researchers are utilizing IL2 and creating this protein in the laboratory to increase the number of cells to combat cancers.
The Federal Drug Administration (FDA) has approved IL2 to treat renal or kidney cancer and
melanoma. Using IL2 as a treatment for pleural mesothelioma is still in the experimental stages. Recent laboratory results with mesothelioma cell lines look promising. Preliminary clinical trials have shown limited success (see Lung Cancer. 2001 Jan, 31(1): 67–72; J Cell Physiol. 2000 Oct, 185(1): 126–34; and Cancer. 1998 Nov 15; 83(10): 2099–104).
Cryoablation is an alternative minimally invasive procedure, showing promise with mesothelioma patients. It uses controlled freezing to dissipate small cancer tumors in a relatively safe and quick manner. With the use of a large needle, compressed argon gas is applied to the targeted tissue, killing the cells it touches.
Used adjunctively with standard therapies for mesothelioma, cryoablation can effectively improve both survival and quality of life. It can be used on surrounding small lesions in order to make a patient eligible for future surgery such as the pleurectomy / decortication (P/D) or extra-pleuralpneumonectomy (EPP) or it can be administered to localized recurrences of disease post-surgically. It can also improve the patient’s quality of life when used in a palliative manner to control the pain associated with invading tumor.
Anti-Angiogenesis Tumor angiogenesis is the proliferation of a network of blood vessels that penetrates into cancerous growths, supplying nutrients and oxygen and removing waste products. Tumor angiogenesis actually starts with cancerous tumor cells releasing molecules that send signals to surrounding normal host tissue. This signaling activates certain genes in the host tissue that, in turn, make proteins to encourage growth of new blood vessels.
Angiogenesis Inhibitors are drugs that block the development of new blood vessels, the process known as angiogenesis. By blocking the development of new blood vessels, researchers hope to cut off the tumor’s supply of oxygen and nutrients. This in turn might stop the tumor from growing and spreading to other parts of the body.
