Mesothelioma and non-small cell lung cancer are cancers but are distinctly different. It is critical to understand the difference between these two types of cancer; the more you know about both, the better you will be prepared to treat them. Below is more information about the characteristics of each cancer and the significant differences between them.
Non-Small Cell Lung Cancer Overview
‘Lung cancer’ refers to cancer that develops inside the lungs. There are two major classifications of lung cancer: non-small cell lung cancer (NSCLS) and small cell lung cancer (SCLS) NSCLC is the most common form of lung cancer. Approximately 85% of lung cancers are non-small cell variety. (Lungcancer.net).
NSCLC occurs when cancer cells form in the lung tissues. Major risk factors for this disease are smoking. Common signs of non-small cell lung cancer are a persistent cough and shortness of breath. NSCLC is different from mesothelioma in that the former is primarily caused by smoking, and the latter by asbestos exposure. NSCLC is more common than mesothelioma, with the latter being diagnosed in only approximately 3,000 people annually. (Cancer.net)
NSCLC has sub-types, as well, that are classified by the type of cancer cells. Each type can be grown and spread in different ways. Determination is decided by viewing the cancer cells under a microscope. This is critical because the classification helps physicians to select the best treatment options, as well as decide the cancer’s prognosis. (Cancer.org)
The most common type of NSCLS is adenocarcinoma, representing approximately 40% of lung cancers. Adenocarcinoma usually forms in a peripheral area of the lung. Sometimes it will develop at the site of scars, wounds, or inflammation. Adenocarcinoma begins in cells in the alveoli. These are tiny air sacs in the lungs that promote the exchange of oxygen and carbon dioxide between the blood and lungs. Other characteristics of the cancer cells under a microscope:
- Acinar: Cells in shape of the alveoli.
- Papillary: The structure of the cell growth.
- Bronchioloalveolar: Subset of adenocarcinoma that grows in the alveoli or outer bronchioles.
- Mucinous: Ability of the tumor to develop mucin, the major component of mucus.
Squamous Cell Carcinoma
This type of non-small cell lung cancer accounts for 30% of lung cancers. It is located in the central areas of the lungs, such as the bronchi. Squamous cells are flat in shape and line the airways. A squamous cell carcinoma may also be described as clear cell, small cell, papillary, or basaloid. These names refer to their shape under a microscope. (Health.Harvard.edu)
Large Cell Carcinoma
This type of non-small cell lung cancer accounts for 15% of lung cancers. It will appear on a chest X-ray as a large mass in the outer parts of the lungs. Under a microscope, large cell carcinomas do not resemble adenocarcinomas or squamous cell carcinomas. These cancer tumors have a favorable prognosis compared to SCLC and are treated like adenocarcinomas.
Less Common Forms of Non-Small Cell Lung Cancer
There are several, rarer forms of NSCLC:
- Adenosquamous carcinoma. It is a cellular structure that is somewhat glandular and partly surface cells.
- Sarcomatoid carcinoma. It is a carcinoma mixture that lines the lungs and sarcomas that are formed in supportive or connective tissue.
- A sarcomatoid subtype that has many shapes.
- Salivary gland carcinoma. It is named for its resemblance to tumors that grow in the salivary glands.
Non-Small Cell Lung Cancer Treatment
Lung cancer, such as NSCLC is very serious, but there some treatment options can prolong life considerably:
- Surgery: Most stage 1 and 2 NSCLCs are treated with surgery to take out the tumors. The surgeon removes part of the lung where tumors are present.
- Chemotherapy and radiation: For people who have tumors removed, research indicates chemotherapy after surgery (called adjuvant chemotherapy) can keep the cancer from coming back. For stage 3, chemotherapy and high dose radiation treatments are often used.
- Chemotherapy alone: Using chemotherapy before surgery or radiation can help patients by shrinking the tumors, so they are easier to take out with surgery. (org)
Mesothelioma Cancer Overview
Mesothelioma develops in the mesothelium. This is a thin membrane that covers your internal organs. It is an aggressive, rare cancer that is almost always caused by asbestos exposure. When the person inhales asbestos dust, tiny shards of the carcinogen can lodge in the lungs. Over the years, changes in the DNA can cause mesothelioma to form.
Doctors divide asbestos cancer into different subtypes based on the part of the mesothelium that has cancer. In most people, the tissue surrounding the lungs (pleura) is affected. This form is called pleural mesothelioma. Rarer forms of mesothelioma affect organs in the abdomen (peritoneal mesothelioma) and even more unusual, the heart (pericardial mesothelioma). (Mayoclinic.org)
Symptoms of mesothelioma depend on where the cancer is forming. For pleural mesothelioma that affects the lungs, frequent signs are:
- Painful coughing
- Pain in the chest
- Shortness of breath
- Lumps of tissue under skin on the chest
- Sudden weight loss
Peritoneal mesothelioma occurs in the abdomen and has these signs:
- Abdominal swelling
- Abdominal pain
- Unexplained weight loss
Pericardial mesothelioma also can have signs such as difficulty breathing and pains in the chest.
Mesothelioma Cancer Treatment
Mesothelioma is notoriously hard to treat, especially in stages 3 and 4. Several factors come into play to determine the best treatments. For example, your doctor will check if the mesothelioma can be mostly removed by surgery. He also will review your general health to determine the treatments to use. The best treatment results are offered by a team of doctors experienced in treating asbestos cancer. (Cancer.org)
Patients with resectable pleural mesothelioma may have the tumors removed with an extrapleural pneumonectomy or pleurectomy/decortication. Surgery usually is most effective for mesothelioma in the early stages.
Patients with stage 1 or 2 peritoneal mesothelioma could benefit from surgery combined with heated intraperitoneal chemotherapy (HIPEC).
If you have stage 4 mesothelioma, it probably cannot be taken out with surgery. This could be because the cancer is widespread, or you are too ill to undergo surgery. Chemotherapy is the best option for mesothelioma at this point. It will not cure mesothelioma, but it can shrink tumors and ease painful symptoms.
Pathology of NSCLC and Mesothelioma
Mesothelioma and lung cancer grow differently. Lung cancer, such as non-small cell lung cancer, develops inside the lungs. (Lungcancer.net).This lung cancer is usually present with distinct tumors in the lungs and has clear borders.
On the other hand, mesothelioma forms in the pleural lining of your lungs. Over time, mesothelioma grows into a tumor network and does not have clear boundaries. The size of the tumor network is usually large.
Staging for both cancers is identical in stages 1-3, where the tumors go from being isolated and localized to spreading into other areas of the body, including the lymph nodes. Staging is different by stage 4, where mesothelioma continues to grow in local tissues, with some spreading to another lung or the bones. Non-small cell lung cancer tends to spread all over the body in the later stages.
It is vital to be examined by your medical professional if you think you have any form of cancer. The sooner the type of cancer is identified, the sooner treatment can begin. Mesothelioma can be confused with lung cancer by some physicians, which is why it is so important to disclose past asbestos exposure to your healthcare professional.