Mesothelioma vs Carcinoma (Squamous Cell)
Mesothelioma is a cancer that is generally caused by asbestos exposure. Carcinoma (squamous cell) is a form of skin cancer. It is important to understand the differences between the two types of cancer, but also what links them together.
What Is Mesothelioma?
Mesothelioma develops in the lining of the body’s organs. It is most common in the lungs, but has also been found in other organs, including the skin. In most cases, it is directly linked to exposure to asbestos. When it affects the lungs, it is known as pleural mesothelioma. When it affects the stomach, which is the second most common place, it is known as peritoneal mesothelioma. The cancer has also been found in the lining of the testicles and the heart. The condition is most commonly diagnosed in people between the ages of 60 and 80, and it is most common in men.
Unfortunately, mesothelioma is usually not diagnosed until it is in its advanced stages. As a result, most people will only receive palliative care to help them live with the symptoms. Common symptoms include:
- Shortness of breath
- Pain in the chest
- Fever, particularly at night, known as night sweats
- Extreme tiredness
- Loss of appetite that goes with weight loss
- Persistent coughs, sometimes with blood in mucus
- Swollen and clubbed fingertips
In cases of peritoneal mesothelioma, common symptoms include:
- Pain and swelling in the stomach
- Feeling nauseous and sick
- Loss of appetite that usually goes hand in hand with weight loss
- Constipation and/or diarrhea
Mesothelioma is usually caused by asbestos exposure. Asbestos is a group of minerals that contain microscopic fibers. The substance is very common in construction. When disturbed, the fibers become airborne and when they are inhaled, they damage the lungs. It is not known how much exposure is required for someone to develop mesothelioma, but it is considered to be dangerous even in very low amounts. Usually, symptoms develop around 20 years after exposure. Asbestos is now banned in construction, but it still exists in older buildings. As such, while cases of mesothelioma are starting to drop, they do still exist.
To diagnose the condition, a number of test can be performed, including:
- CT scans
- Fluid draining
Usually, when mesothelioma is discovered, it is already in an advanced stage and this makes treatment very difficult. Nevertheless, in cases where it is discovered early enough, common treatment options include:
Squamous Cell Carcinoma
Carcinoma is skin cancer, which can either be with or without melanomas. Squamous cell carcinoma is a type of non-melanoma cancer. It is usually caused by overexposure to UV radiation. As a result, the keratinocytes in the epidermis grow out of control and start to form a tumor. Squamous cell carcinomas can appear anywhere on the body, but they are most common on the neck, face, and the back of the hands, which receive the most sun exposure.
A number of people are most at risk of developing squamous cell carcinoma, which are:
- The elderly
- People who work outside, such as sailors, surfers, farmers, and builders
- People with very fair skin
- People who have had UV treatment on conditions like psoriasis
- People with a suppressed immune system
There is no proven genetic link with squamous cell carcinoma. However, some of the risk factors such as having fair skin are hereditary. It is important to be safe and to check yourself regularly if you do have fair skin.
A squamous cell carcinoma usually starts as a spot with an inflamed base and a crusty top. They are usually not painful. A physician can investigate these further by taking a biopsy of the spot, or an excision biopsy of the entire area to determine whether or not it is actually cancerous.
Squamous cell carcinomas can be cured so long as they are detected on time. If they are left unattended, however, it is possible for the cancer to spread to other parts of the body. At this point, treatment becomes much less effective.
Skin Tumors and Mesothelioma
So what is the link between mesothelioma and squamous cell carcinoma? Essentially, if people have certain skin spots, they may be at a greater risk of developing mesothelioma. The University of Hawaii has made new discoveries that demonstrate that people who have tumors that look like moles, or people who have a BAP1 gene mutation, are more likely to develop mesothelioma. Thanks to this discovery, it may soon be possible to diagnose mesothelioma in much earlier stages, thereby also increasing the likelihood of the illness responding properly to treatment. The BAP1 gene is a gene that is believed to suppress tumors, thereby restraining cancer. If the gene is mutated, however, it is no longer able to fight cancer. What the new research has shown is that people with mesothelioma are more likely to have a BAP1 gene mutation as well. Put together with other pieces of research, scientists now know that people who have mole like tumors are more likely to develop mesothelioma as well. In fact, it is believed that the marks on the skin may be the very first clinical manifestation of BAP1 cancer syndrome.
In the research, 118 people were studied. It was found that those who had the skin tumors were far more likely to also have mesothelioma. This means that there is a definitive relationship between the cancerous growths, a mutation in the BAP1 mutation, and mesothelioma.
Every year, some 3,000 cases of mesothelioma are still diagnosed every year. The majority of these cases are found to be advanced stages. In fact, the prognosis for someone who is newly diagnosed is a life expectancy of no more than 18 months. However, as a result of the study, clinical trials have started for a new immunotherapy drug, which showed that 76% of those who tried it saw the growth of their malignant pleural mesothelioma fully halted. The drug, Pembrolizumab, was tested on 25 patients who all had mesothelioma and in whom standard chemotherapy had failed. They were administered Pembrolizumab and seven people saw their tumor shrink, while 12 saw that there was no further growth. Just four said their tumor had continued to grow (the remaining two were not assessed).
This success rate of 76% is incredibly promising. A phase 2 clinical trial has now started for the drug, and new patients have to be recruited for this. To date, the FDA (U.S. Food and Drug Administration) has not approved any post-first line therapies. However, they did approve Pembrolizumab for the treatment of a rare skin cancer type, which is metastatic melanoma. Some 88 different clinical trials are currently taking place into the drug.
There is, clearly, a link between mesothelioma and squamous cell carcinoma. This link is strong in how the condition presents itself, not in its pathophysiology, however. Rather, the two often happen together and have a significant overlap in symptoms.