Conventional mesothelioma treatments include surgery, chemotherapy and radiation therapy. However, experimental treatments may be an option for patients not responding to standard options, if they are eligible.
Treatment techniques begin in the experimental stage as they are still being tested and improved through clinical trials. If they show enough success, they may be offered as a standard treatment option after being approved by the U.S. Food and Drug Administration (FDA). Experimental treatments are constantly emerging as researchers look for more effective treatment options and a cure for mesothelioma cancer. Patients interested in undergoing experimental treatments must meet individual clinical trial criteria and should discuss with a mesothelioma specialist to determine the best treatment option.
Immunotherapy is a mesothelioma treatment that boosts the immune system as a way to fight mesothelioma. Currently, there are two main immunotherapy techniques, including active immunotherapy and passive immunotherapy.
- Uses immune memory, which allows the immune system to quickly recognize an antigen and react accordingly.
- Evokes a long-lasting response that stimulates immune cells to act against cancer cells when they are present.
- Synthetic immune proteins are introduced to the body to trigger a response to fight cancer.
- Immune memory is not triggered, so the response is temporary and multiple immunotherapy treatments may be required.
There are different types of active and passive immunotherapies, including adoptive cell transfer, cancer vaccines, immune checkpoint inhibitors and monoclonal antibodies. Each of the four main types has its own benefits and risks, which patients should discuss with their doctor prior to consideration.
Immunotherapy drugs as part of a multimodal treatment plan have shown promising success, particularly in combination with chemotherapy. In some clinical trials, researchers have seen patient’s life expectancies extend to two or more years. Immunotherapy is currently only available to mesothelioma patients through clinical trials, so they must meet certain criteria to participate.
When a patient has malignant mesothelioma, their healthy cells have mutated into cancer cells. Gene therapy works to treat cancer by introducing new DNA into the patient in an attempt to replace missing or defective genes caused by cancerous mutations, or to create a beneficial protein. In some cases, a replica of the normal gene is introduced to restore its original function.
Researchers continue to develop new ways of introducing gene therapy to patients, but currently, there are three main types used to treat mesothelioma.
- Angiogenic Inhibitors: Tumors rely on blood supply to signal and trigger angiogenesis, which is the forming of new blood vessels and growth of cancer. Angiogenic inhibitors block this growth and are often used in combination with chemotherapy or radiation therapy as they don’t kill the cancer.
- Gene Transfer: Gene transfer introduces genes to cancer cells to slow tumor growth or kill the cancer cells altogether. Suicide gene transfer therapy is the most common, killing the cancer cells.
- Oncolytic Virotherapy: Oncolytic therapy introduces a virus in an attempt to break down mesothelioma cells and leave healthy cells unharmed. Weakening these cells can increase the efficacy of chemotherapy and radiation therapy, aiding in a multimodal treatment plan.
One gene that has shown particular interest in the treatment of mesothelioma is the p53 gene. The p53 gene plays an important role in preventing tumor growth, and most cancers demonstrate a mutation of this gene. When mutated, it no longer works as a tumor suppressant, allowing for cancer growth. To treat mesothelioma, researchers seek to repair the gene’s function, allowing it to function normally and prevent metastasis. Though promising, gene therapy is only available through mesothelioma clinical trials, as the risks and potential successes are still being assessed.
Epigenetic therapy is similar to gene therapy, as it targets changes in DNA. The main difference between gene therapy and epigenetic therapy is that epigenetic therapy focuses on changing DNA expression instead of altering the DNA sequence itself. This type of treatment uses drugs to target epigenetic changes, reverse any damage and return natural and normal DNA gene expression. Currently, epigenetic therapy is being tested on a variety of cancers, including mesothelioma, metastatic breast cancer, lymphoma and lung cancer with some drugs gaining FDA approval.
Researchers have noted that there are epigenetic changes in mesothelioma patients, focusing particularly on pleural mesothelioma. Malignant mesothelioma research suggests that certain changes in DNA expression can contribute to the growth and development of cancer, and some studies have shown epigenetic alterations in malignant pleural mesothelioma patients who are not responding to chemotherapy drugs. Studies have also found a connection between epigenetic changes and the presence of asbestos fibers within the lungs, as well as with epigenetic changes and survival rates of pleural mesothelioma patients.
Photodynamic therapy (PDT) is an emerging mesothelioma cancer treatment that has shown early success. Mesothelioma photodynamic therapy uses light and drugs known as photosensitizing agents to kill cancer cells and stop the cancer from spreading.
This treatment technique has been of particular interest to researchers because of the lack of side effects, which could help improve quality of life for patients. With added success, photodynamic therapy may emerge from its experimental stages into a conventional treatment option. One recent study noted that intraoperative photodynamic therapy combined with lung-sparing surgery greatly extended life expectancies for malignant pleural mesothelioma patients.
Mesothelioma specialists have studied the use of cryotherapy in treating mesothelioma. Cryotherapy, otherwise known as cryosurgery and cryoablation, kills cancerous mesothelioma cells by exposing them to extremely cold temperatures.
Cryotherapy goals may include shrinking or eliminating a tumor, reducing mesothelioma symptoms and/or preventing recurrence. Some studies have seen success, but its effectiveness is still being tested.
Patients interested in undergoing an experimental treatment option should discuss the possibility with their medical care team. Clinical trials have certain criteria that a patient must meet to participate, such as the type of mesothelioma and stage of their cancer. Patients should also discuss whether or not experimental techniques are the best option for their individual case.
A multimodal treatment approach is very common for mesothelioma patients. Multimodal treatments often combine surgery, chemotherapy and/or radiation therapy, using different techniques based on the individual case. Ideally, patients are able to undergo surgical resection to remove as much of the cancer as possible, followed by chemotherapy or radiation therapy to kill any remaining cancer cells and help prevent recurrence.
Though this traditional multimodal treatment is readily available to most mesothelioma patients, researchers are still testing the effectiveness of different treatment techniques and the order that they are administered. For example, hyperthermic intraperitoneal chemotherapy is a relatively new treatment that has shown much success in treating peritoneal mesothelioma, combining surgery with a warm chemotherapy wash. The success of this treatment offers hope for other combinations and innovative techniques that may effectively treat mesothelioma cancer and extend patient survival.
Author: Linda Molinari
Editor in Chief, Mesothelioma Cancer AllianceRead about Linda
Reviewer: Annette Charlevois
Patient Support CoordinatorRead about Annette
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