Mesothelioma is a cancer of the mesothelium. The mesothelium is the outer layer of most internal organs and body cavities. The pleural cavity, peritoneal cavity, pericardial cavity, and tunica vaginalis are the most common body cavities, that have mesothelium as an outer protective and lubricative layer.
To have an understanding of the function and structure of mesothelium, take it as an outer thin layer that has mesothelial cells. The mesothelial cells are flat and squamous and are supported by connective tissue. It is the thin layer that most apparently functions as a lubricative and protective layer. Mesothelial cells are connected to each other by tight junctions, called desmosomes. Desmosomes make mesothelium a good barrier against physical traumas and chemical reactive agents.
In this blog, one will understand how asbestos exposure becomes the cause of mesothelioma and which people are at the most risk of developing mesothelioma. Although asbestos exposure is its major cause, some other factors may also trigger mesothelioma. Genetic predisposition, environmental factors, and hygiene are also related to the spurring of mesothelioma. For a general understanding, asbestos is a chemical substance that has microscopic needle-like structures. When such microscopic needles make it to the inside of the body, they get entangled in the thin and connective tissue layer, mesothelium. The part of the body which affected mesothelium is protecting, becomes prone to deterioration or damage as its protective layer becomes faulty.
Asbestos fibers, when stranded in the thin and meshy mesothelium causes mesothelioma.
The Possible Treatments of Mesothelioma
The following is an overview of all possible treatments for mesothelioma. For opting out of the appropriate method, clinical trials with an experienced doctor are recommended. This blog is just for informational purposes as if one would have the comprehensive understanding of almost all possible treatments for mesothelioma, it would be easy for him to consider the treatment strategy.
1. Surgery:
Pleural mesothelioma is the most common form of mesothelioma. Lungs in the chest cavity are surrounded by a pleural cavity. All major internal organs have their own cavities to provide lubrication to the organ movements and reduce friction. For example, the heart is in the pericardial cavity, protected by pericardial mesothelium. Similarly, lungs are present in the pleural cavity, lined by pleura. The pleura is a double-membraned structure having an outer pleural and an inner pleural membrane.
So, here we will see some surgical procedures as the possible treatments for mesothelioma that are related to the removal of cancer growth (tumors) affecting pleural mesothelium.
Removing the Whole Lung or The Outer Regions of the Pleural Cavity
Extra Pleural Pneumonectomy (EPP) is the surgical term for the removal of the whole affected lung. It also involves the removal of tumors outside the lungs, but in the pleural cavity or near to pleural cavity. Such conditions involve cancerous growth in the pleural mesothelium or nearby diaphragm region. Sometimes, the metastasis also reaches the pericardium.
Sparing The Lungs
Pleurectomy or decortication is the surgical removal of tumors in the pleura. It does not involve removing the whole lung, but it focuses on only removing the specific tumor part. It is done for soothing pain and chest symptoms, but cannot serve as the ultimate treatment for pleural mesothelioma.
Cytoreductive Surgery
Cytoreductive surgery is the removal of diseased peritoneal mesothelium. The peritoneum is the covering of the peritoneal cavity (abdomen). Such surgeries are followed by heated intraperitoneal chemotherapy (HIPEC). HIPEC serves to kill the remaining cancer cells in the peritoneal cavity to minimize the chances of cancer regrowth.
Besides these basic surgical procedures, some other surgeries can be added to the list of possible treatments for mesothelioma. Remember that, surgery should not be the foreboding step for the treatment of mesothelioma. Surgery is usually the ultimate treatment of mesothelioma or any cancer or tumor growth if it persists even after other treatments, such as chemotherapy, radiotherapy, or immunotherapy.
The following are some other surgical procedures for mesothelioma;
Percardioctomy
Thoracentes
Pleurodesis
Surgical Operations are one of the most practical approach to remove tumors, also in the case of mesothelioma. However, if the cancer spreads and it’s difficult to localize the tumor presence, surgical procedures then may not be the best option.
2. Chemotherapy
It is one of the possible treatments for mesothelioma that oncologists rely on at early stages. Chemotherapy and radiotherapy are the earlier steps to shrink cancer growth prior to surgery. However, the conditions vary depending on the location and grade of mesothelioma.
The common principle of chemotherapeutic agents in the domain of cancer treatment is almost the same. Most chemotherapeutic agents damage or spoil the DNA or RNA of cancer cells to stop their voluntary spreading and monitoring. Some chemotherapeutic agents also target the enzymes (proteins) which are essential for DNA or RNA replication. Their ultimatum is to cease the growth of cancer cells. The best way to target their control center is their genetic material. So, chemotherapeutic agents do the same.
The following are some famous chemotherapeutic agents which can be helpful in the handling of mesothelioma;
Cisplatin
Carboplatin
Pemetrexed
Gemcitabine
3. Radiotherapy
Radiotherapy or radiation therapy works on the energy of radiation to destroy desired cells. Here, what we mean by desired cells are the cells we want to damage by high-energy radiation beams. In radiation therapy, one most common and legitimate concerns is the chances that radiation may also cause genetic mutations in the nearby healthy cells. If it does happen. radiotherapy causes more damage than treatment. Yes, radiotherapy is an effective strategic treatment of target specificity is maintained and that is not so easy. But, it can be possible. For example, if the tumor is larger then, radiation can be used to target a wide area and are effective as compared to a narrow target range. Targeting a narrow range increases the chances that radiation might damage the nearby cancer cells.
4. Immunotherapy
Immunotherapy takes the plunge of bolstering the body’s natural immunity with the help of therapeutic medicines or drugs. Immunotherapeutic drugs can come under the chemotherapy domain. Chemotherapy, as we have seen, contains drugs that suppress or annihilate the growth of cancer cells. Immunotherapy also aims to destroy cancer cells but with a slight twist. Instead of directly attacking cancer cells, immunotherapeutic agents target the immune cells of the body.
Immune cells contain proteins or receptors. These drugs target such proteins present in the immune cells. By causing some structural and functional changes, they enhance the effectiveness of immune cells, making them stronger defense cells against cancer.
So, in simple wording, immunotherapy harnesses the city’s police to capture the thieves, instead of directly running after them thieves. They’re playing smart!
However, some immunotherapeutic agents are also designed to target cancer cells. The proteins or receptors, that immune cells have which immunotherapeutic agents target, are also present on the cancer cells. Some structural differences can persist. The drugs have monoclonal antibodies. Monoclonal antibodies mean they have antibodies that are cloned from the same species and type. All monoclonal antibodies would have a specific target, such as PD-1 on immune cells. Such molecules can also be present in cancer cells and immunotherapeutic agents are designed to aim them.
Chemotherapy and immunotherapy treatment options are based on the latest molecular studies to manufacture the effective drugs for treating cancer.
Below are some examples of immunotherapeutic agents;
Pembrolizumab (Keytruda): It targets the PD-1 protein in the immune cells. Making them an objective, that enhances the effectivity of immune cells to recognize and fight cancer cells.
Nivolumab (Opdivo): It acts on the same principle as pembrolizumab, upgrading the immune cells to target the cancer and amplify their destruction.
Atezolizumab (Tecentriq): It works by locking onto the cancer cells instead of immune cells. Atezolizumab takes aim at the PD-L1 protein in the cancer cells. By setting that protein as an aim, this drug helps the immune cells to recognize the cancer cells that have structural conformity in their surface PD-L1 protein. It makes their recognition and destruction easy.
5. Targeted Therapies
It is a treatment option in the possible treatments of mesothelioma. Targeted therapy is specific and targets a protein or a receptor that is worth targeting. The proteins or small molecules that play a vital role in the development of cancer cells by providing them with nutrients and oxygen become the target.
For example, vascular endothelial growth factor (VEGF) is a protein that promotes the formation of new blood vessels (angiogenesis) in the cancer masses. Angiogenesis helps the cancer to spread and damage other body cells. It provides essential blood supply to the proliferating (dividing) cancer cells. Targeted therapy, when taking a shot at VEGF, minimizes the chances of cancer spreading. Bevacizumab (Avastin) is a drug that aims on VEGF. Similarly, another protein receptor, epidermal growth factor receptor (EGFR), facilitates the spread of cancer by amplifying its proliferation. Erlotinib (Tarceva) specifically targets EGFR to alleviate the division of cancer cells.
Targeted therapies have become a widely practical treatment option in many types of cancers, including breast cancer, lung cancer, colorectal cancer, etc. However, in mesothelioma, it is still under investigation and research phase. So far, scientists and doctors have recorded positive results in the pre-clinical trials and lab findings. If targeted therapy becomes one of the possible treatments for mesothelioma, it would be a milestone in the scope of treating mesothelioma.
In a Nutshell
In a nutshell, the above are the currently established possible treatments for mesothelioma. Moreover, besides these medical treatments, palliative care also brings a change in the recovery of patients. Palliative care aims at improving the quality of life by relieving pain and other such symptoms. When a patient experiences a healthy or quality life experience even if he’s fighting the cancer, the chances for his recovery improve a lot. The choice of treatment is not based upon the willingness of the patient to what treatment option, he wants to go with. Although some choice depends upon the willingness of the patient, mostly it depends on the stage of mesothelioma, the professional advice of a doctor, and the clinical findings.
