Asbestos – The Only Identified Cause of Malignant Mesothelioma

Malignant mesothelioma is a deadly, but rare form of cancer that develops in the thin membrane that protect most organs in the body including the lungs, heart, and the abdomen. Research has indicated that malignant mesothelioma is caused by exposure to asbestos 1,2,3, that’s the reason it’s sometimes referred to as asbestos cancer. People who think they may have been exposed to asbestos at workplace, at home, or other environments, they need to seek medical help for early screening. One big problem that has been seen with mesothelioma is it’s latency period – it has a long period for it to be diagnosed something that has made its prognosis to be poor and the life expectancy to be short.1

How Asbestos Causes Mesothelioma

As of today, exposure to asbestos may be said to be the only known cause of malignant mesothelioma. People who ingest or inhale asbestos will have the microscopic fibers getting lodged in the lining tissue of organs like the abdomen and chest.

In March 2009, IARC or the International Agency for Research on Cancer reconfirmed that the leading cause of malignant mesothelioma is asbestos exposure, and all asbestos forms cause the cancer. About two years after this reconfirmation, IARC did a presentation showing the connection between cancer and asbestos at WHO conference in Spain. In the presentation, IARC said that scientific evidence confirming asbestos exposure as the main cause of mesothelioma has been strengthening over time.1

What’s Asbestos?

Talking of asbestos, it’s a naturally occurring mineral that has been used for many centuries. It has been used in products including insulation and textiles. The mineral saw an increased usage in early to mid of 20th century recording its peak of usage in USA during the Second World War. Not until 1980s was its commercial usage stopped.1

asbestos

Asbestos on floors roofs pipes ceilings

Despite the curb of using asbestos for commercial applications, people are still likely to be exposed to the mineral. This substance consists of flexible, microscopic fibers deemed to be lighter than air, but with high tensile strength. A fiber of asbestos is considered to be a hundred or so times thinner when compared to the human hair.

asbestos fibers

Asbestos Fibers

Uses of Asbestos

The substance has high resistance to corrosion, water, and heat damage, and this is one reason why it gained popularity in usage within a range of industries and applications including building insulation, brake pads for cars, and gaskets.

Asbestos found in Uses of asbestos

Types of Asbestos

The main categories of asbestos are amphibole and serpentine, and they are categorized by the shape the fibers assume. Serpentine has wavy fibers and is said to be found in about 95% of products developed for commercial use in USA. Since serpentine fibers are light and wavy, they can easily be breathed out from an individual’s body when compared to amphibole fibers. 1,2,3,4

The other main category, which is amphibole consists of spindle-shaped fibers that tend to be rigid, sharp, and have the ability to lodge themselves in the tissue of the body. It is this property of amphibole that increases the risk of an individual developing mesothelioma.

Besides the two categories, there are six types of the mineral, but two of them namely: tremolite and actinolite, are not used commercially. The other four, and which are found in many products and materials are:1,2,3

Anthophyllite

  • These appear gray and are used in different commercial applications

Crocidolite and Amosite

These appear blue and brown respectively, and they are used in spray-on insulation and on ships. Both of these types of asbestos take a brittle, needle-like structure making them to be difficult to dislodge or come out of the respiratory tract.

Chrysotile

These are white in appearance and are a form of serpentine asbestos (the only serpentine asbestos we have). Chrysotile has curled fibers and it’s one of the most used in commercial applications. These asbestos fibers can be dislodged from a person’s body much easier compared to the other forms.

Asbestos Types Images Asbestos Types

Kinds of Asbestos Exposure

People may be exposed to asbestos in different ways including:1

Occupational

This involved people being directly exposed to the mineral at their jobs. People who worked in construction or industrial trades or those who came in contact with products used in these applications may have been exposed to the fibers. Another name for occupational exposure is first hand exposure to asbestos.

Secondhand

There are cases where people were exposed to the mineral after coming in contact with clothes of persons who worked with or near the substance.

Environmental

Because the mineral may be found in nature, for example in mines, it means that people near those locations may have been exposed to the fibers released into the air.

How Does Asbestos Cause Mesothelioma?

Various studies explore the way in which asbestos causes mesothelioma. An expert in mesothelioma Dr. Michele Carbone who is also the director of thoracic oncology within the University of Hawaii Center did feature in co-writing a scientific piece in 2012 that detailed the various ways asbestos could damage an individual’s body.

In the publication, Dr. Michele Carbone said that asbestos may damage the body by creating inflammatory chemicals that bring about direct genetic damage. Of course, there are other theories that try to highlight how this substance is likely to cause malignant mesothelioma.2

The development of mesothelioma may not occur with little exposure to asbestos, it usually has to be a heavy, long-term exposure. That said, even minor exposures may be harmful. If products containing asbestos fibers are disturbed, they release the mineral into the air, and because there is a dose-response relationship for mesothelioma to asbestos, it means that exposing yourself to high doses of the substance leads to greater risks of having mesothelioma.

In the body, asbestos may build up in organs like the lungs and areas such as the abdomen because the fibers are sharp or even jagged shaped for them to be expelled out of the body. After a long time of having asbestos exposure, a person may begin to have cancerous changes that start in mesothelial cells comprising the tissue lining the heart, lungs, and abdomen.2

Asbestos affected Lungs causing mesothelioma

Theories on Development of Asbestos Related Tumors

There are different schools of thought when it comes to the way asbestos may cause tumor development and they include:

Genetic changes

When the asbestos fibers get into the mesothelial cells, they cause disruption on the life cycle of the cells something that induces changes in DNA leading to development of cancer.

Inflamed cells

The fibers may cause irritation and inflammation of the mesothelial cells leading to irreversible scarring, damage to the cellular structure, and development of cancer.

Cancerous mutations

The fibers lead to free radicals in body, which cause damage to the DNA making healthy cells to mutate and become cancerous.

Uncontrolled growth

The asbestos fibers may trigger the release of oncoproteins, and these kinds of proteins block genes responsible in protecting the cells from uncontrollably growing and forming tumors.

When you look at these theories, you will find a common ground that asbestos fibers change the life cycle of cells.

Healthy cells have genes able to regulate and protect the body against cancer and when the asbestos block this function, you may find the cells begin to divide uncontrollably leading to formation of malignant tumors whether localized or metastasized. The tumors tend to develop later on when mesothelioma has already started, but it’s one of the clinical symptoms of the cancer. Some types of asbestos are more carcinogenic compared to others, for example crocidolite and amosite.

Reference List

  1. CAUSES OF MESOTHELIOMA. Available at https://www.mesotheliomagroup.com/mesothelioma/causes/
  2. Mesothelioma Causes & Risk Factors. Available at https://www.asbestos.com/mesothelioma/causes.php
  3. Asbestos Cancer. Available at https://www.mesothelioma.com/asbestos-cancer/
  4. Asbestos – The Primary Cause of Mesothelioma. Available at https://www.mesotheliomaguide.com/mesothelioma/causes/asbestos/

Mesothelioma

What is Mesothelioma?

If you have a patient who suffers from mesothelioma or you have worked in an area thought to have exposure of asbestos, you may want to know what is mesothelioma, who develops this form of cancer, and what is the prognosis of the cancer and treatment options available.

mesothelioma

Mesothelioma is an aggressive, but rare form of cancer known to develop in lining of organs like the lungs, heart, and the abdomen. It is known to be caused by asbestos, but there is no known cure for it. This disease has a very poor prognosis.

In the United States, it’s estimated that about 2,400 to 2,800 persons are diagnosed with this form of cancer every years, according to a report published by Centers for Disease Control in 2017. People who work or worked in areas with asbestos exposure have a higher risk of having mesothelioma. It can take many people a long period before the symptoms of mesothelioma appear, typically between 20 to 50 years1.

What is mesothelioma, location of mesothelioma

Again, because there is no known cure of this disease, the life expectancy is seen to be poor. Looking at the survival of a patient, it will depend on factors such as cell type, the stage or phase in which the disease is at the time of diagnosis and treatment, and the location where the tumor is found. There are also other factors that impact prognosis of mesothelioma and they include age, overall health, and if the cancer has spread.

In the United States, the rate of mesothelioma increased in the period between 1970s to early 1990s, however, since then, its rate has leveled off sometimes going down slightly. The changes in rate of mesothelioma have been noted mostly in men, and they occurred because of workplace exposure to the substance that is believed to be the primary cause of the cancer. That’s asbestos. 3

mesothelioma asbestos

The Mesothelium

In the chest and abdomen, there is a layer made up of specialized cells known as mesothelial cells. The same cells are found lining the space around a person’s heat.

So, what is mesothelium?

Mesothelial cells cover outer surfaces of most internal organs and the lining the cells form is referred to as mesothelium. The lining helps to protect organs by forming a special fluid lubricating substance that makes it safe for organs to be able to move against one another.4

Think of it this way, in the chest, you have lungs moving (contracting and expanding) when you breathe, and they don’t rub or damage each other. The lining is named according to the different areas of the body it’s found in, for example, pleura is the lining of mesothelial cells that coats the lungs as well as the space within the chest where lungs are situated.

There is also peritoneum lining that is found inside the abdomen and other organs in that location. The pericardium is a form of mesothelial cells lining (mesothelium) that covers the heart; it also forms the space holding the heart within your chest. There is also a layer of lining that lines the testicles, and it’s called tunica vaginalis. These layers of mesothelial cells can start developing cancer caused by asbestos leading to various names of the specific types of mesothelioma.4

mesothelial cells mesothelium

Mesothelial tumors may begin forming in any of the said linings, and they can be cancerous meaning malignant or non cancerous meaning benign. A patient having malignant mesothelioma may show symptoms such as:

  • Pain under their rib cage
  • Trouble breathing
  • Pain, lumps, or swelling felt in the abdomen
  • Having weight loss without any obvious or known reason.5

Treatment of Mesothelioma

While the mesothelioma treatment a patient gets depends on their health and other aspects like location and stage of cancer, you find that because it an aggressive form of cancer, by the time it’s detected, it has already done a lot of damage. Diagnosis is often done at an advanced stage, a time which it’s not possible to treat or remove it through surgery.6

Prognosis for Mesothelioma

Sadly, prognosis of asbestos cancer or mesothelioma is pretty poor, most patients will live less than one year after they are diagnosed. The prognosis for this form of cancer may be improved if a patient is able to get tailored, individualized treatment soon they are diagnosed with the disease and change their lifestyle to lead a healthy life. One thing that makes prognosis to be poor is because malignant mesothelioma has an extended latency period, it takes long for it to be detected so by the time a patient has been diagnosed, it has already advanced in stage.

Life Expectancy for Mesothelioma Patients

Unfortunately, many patients who have been diagnosed with mesothelioma don’t live for long, they survive for about 12 to 21 months7. That said, the life expectancy for patients with mesothelioma depends upon many things including the stage of the cancer, age of the patient, and their overall health. Fewer than 10% of patients will make it past the 5th year after their diagnosis.

Reference List

  1. Mesothelioma Cancer. Available at https://www.mesothelioma.com/mesothelioma/
  2. Mesothelioma. Available at https://www.asbestos.com/mesothelioma/
  3. What Are the Key Statistics About Malignant Mesothelioma? Available at https://www.cancer.org/cancer/malignant-mesothelioma/about/key-statistics.html
  4. What Is Malignant Mesothelioma? Available at https://www.cancer.org/cancer/malignant-mesothelioma/about/malignant-mesothelioma.html
  5. Mesothelioma. Available at https://medlineplus.gov/mesothelioma.html
  6. Mesothelioma: Overview. Available at https://www.mayoclinic.org/diseases-conditions/mesothelioma/symptoms-causes/syc-20375022
  7. Mesothelioma Life Expectancy. Available at https://www.mesothelioma.com/mesothelioma/prognosis/life-expectancy.htm