Primary and Secondary Lung Cancer

Cancer is a disease related to the uncontrolled growth of tissue, leading to the accumulation of mass (called a tumor or lesion.) Normal cells in the body divide and grow in an orderly controlled manner. When cells grow uncontrollably and this growth invades other tissues or organs, the growths are called malignant or cancerous. When a mass of tissue, or tumor, is benign, it is relatively stable and does not invade other tissues.

Cells from malignant tumors can break away and travel to other parts of the body, usually through the bloodstream, but also through the lymph system. When these cells find new host organs, these cells can grow into tumors in the new tissue. This spreading process is called metastasis and when a cancer has reached an advanced stage to where the malignant cells are attacking other organs, it is said that the cancer tumors have metastasized. The tumors in new organs are always made up of cells similar to those of the original tumor.
Benign tumors do not metastasize. They can often times be removed through surgery and not re-occur.
Lung Cancer
Lung cancer occurs when lung tissue develops cancerous growths. Primary lung cancer is cancer that originates in the lung tissue. Secondary lung cancer is cancer that spreads, or metastasizes, from other organs.
Primary Lung Cancer
There are several different types of primary lung cancer. These are divided into two main groups:
Small Cell Lung Cancer
Non-small Cell Lung Cancer

Pleural mesothelioma is often thought of as a third type of primary lung cancer. However, it is not a lung cancer. Mesothelioma does not develop in the lungs, but in the serous membranes surrounding the lungs. As such, it does not fall into the typical categories of lung cancer. Mesothelioma can also occur in other tissues, in the lining of the abdomen, call peritoneal mesothelioma, and in the lining of the heart, pericardial mesothelioma.
Small Cell Lung Cancer
Small Cell Lung Cancer comprises approximately 20% of the primary types of lung cancer. It is called small cell cancer because the tumor cells are very small, with the cells containing almost exclusively the cell nucleus and nothing more. This type of cancer is also referred to as “oat cell” cancer. Chemotherapy is often suggested for this cancer in the early stages because of the rapid way it which it spreads. Surgery is not a good option to stop the spread early on. This type of cancer is most closely linked to smoking; non smokers rarely have it.
Non-Small Cell Cancer
Non-small cell cancer falls into these categories:
Squamous cell carcinoma
Adenocarcinoma
Large cell carcinoma
Adenosquamous cell carcinoma
Undifferentiated carcinoma
Each category of non-small cell cancer are physiologically similar and they respond to treatment differently than to small cell lung cancer.
Squamous cell carcinoma is a common type of primary lung cancer. This type of cancer is also linked to smoking and it develops from the cells than line the airways in the lungs. Squamous cells are thin, flat cells that look like fish scales. Commonly the tumor growths are located in the center of the lungs near the large airways (bronchi). It is also referred to as epidermoid carcinoma. It comprises approximately 30 to 35% of the non-small cell cancer in the US, affecting men and the elderly most frequently.
Adenocarcinoma, like squamous cell carcinoma, develops from tissues in the lung airways. But, it develops from the glandular secretory tissues. (tissues that produce mucus). It is often found in the outer airway passages, not the main bronchi, like the squamous cell variety. The incidence of this cancer is increasing. It comprises about 40% of the non-small cell lung cancer in the US and is the most common lung cancer among women.
Large cell lung cancer is named after its appearance. The cells look large and unnatural under the microscope. These types of cells grow quite quickly.
Adenosquamous carcinoma are cells that appear flat under the microscope, like the squamous cells, but derive from the glandular secretory cells, like the adenocarcinoma.
Undifferentiated carcinoma includes cancer cells that cannot be identified as one of the other groups. The cells appear abnormal under the microscope and multiply uncontrollably.
Secondary Lung Cancer
Secondary lung cancer is cancer that has spread to the lungs from other organs. Many different types of cancer spread to the lungs, because of its very high blood supply. These include breast cancer and colon cancer.
The type of cancer is very important when it comes to treatment. The different types of cancer cells respond differently to different types of chemotherapy and other therapies. When cancer cells spread from other organs to the lungs, then the lungs have to be treated for the other type of cancer, not lung cancer. This is an important distinction. For example, breast cancer that spreads to the lungs, has to be treated for breast cancer, not lung cancer.

Mesothelioma Symptoms

Mesothelioma symptoms are not specific to the disease, that is, many of the mesothelioma symptoms are the same for other medical problems. Also, most studies show that mesothelioma can occur as much as 30 to 40 years after exposure to asbestos. Thus, when a mesothelioma symptom occurs, many mesothelioma patients do not know that the symptoms they experience are related to something that happened much earlier in their lives. In reality, only a short time period of asbestos exposure, as little as a few months, can create the conditions for a disease that erupts much later in life.

Mesothelioma affects the lining of various cavities in the body. Over time, the growth of the cancerous tumors causes these tissues to expand and gather fluid. The presence of excess fluid is typically what causes the symptoms to occur. The symptoms of the disease will also depend on the location of the tumors.
Pleural Mesothelioma Symptoms
For pleural mesothelioma, which is in the lining surrounding the lung, shortness of breath, chest pain and a persistent cough are common symptoms. Unfortunately, these symptoms are also very common for a number of other ailments, including pneumonia. The most common presenting symptom is localized chest pain, but this may not occur until the disease is well advanced. Coughing and weight loss are not uncommon. Some patients show virtually no symptoms.
Peritoneal Mesothelioma Symptoms
Peritoneal mesothelioma is a cancer of the abdomen lining. Symptoms include swelling or a mass in the abdomen, weight loss and abdominal pain. Also, bowel obstruction and blood clots have been known to occur. Fever is sometimes present.

Pericardial Mesothelioma Symptoms
The lining of the heart is called the pericardium. Pericardial mesothelioma affects this heart lining, causing fluid to gather. Symptoms include chest pain, cough, irregular heart beating and irregular breathing patterns. Many of these symptoms would manifest themselves when patients exert themselves, even with minimal exertion. This type of mesothelioma is the most rare.
With any cancer, the earlier the disease can be detected, the better the prognosis for a treatment that halts the progression.

Diseases of the Lungs and Mesothelium

Mesothelioma is a rare disorder and is often misdiagnosed. It is a disease that derives directly from the mesothelial cells in the serous membranes. But it is not uncommon for other growths to appear in the mesothelium, both cancerous and non cancerous.

Tumors of the mesothelium can be benign (non-cancerous) or cancerous. A malignant tumor of the mesothelium is called malignant mesothelioma, but because most mesothelial tumors are cancerous, the disease is often simply called mesothelioma.
Benign Tumors
Although uncommon, the mesothelium of certain female and male reproductive organs may develop a benign tumor called an adenomatoid tumor. In men, the tumor starts in the area where the sperm is carried from the testicles and in women it starts in the fallopian tubes. Another type of benign tumor that starts in the female reproductive organs is called a benign cystic mesothelioma.
A type of benign tumor that used to be called benign fibrous mesothelioma can form in the pleura around the lungs. It is now known that this type of tumor starts in the tissues under the mesothelium and therefore is not a type of mesothelioma. It is typically not cancerous, but can progress to cancer in some cases. A similar disease that forms in the peritoneum is called a fibrous tumor of the peritoneum. These types of tumors are often removed surgically, and no other treatment is needed.

Malignant Tumors
The most common form of malignant tumors in the mesothelium are metastatic tumors. That is, the tumors start in another part of the body and then the cancer metastasizes and spreads to the mesothelium. The ratio is between 7: 1 to 20: 1 for the occurrence of these types of tumors versus a mesothelioma. Mesothelioma derives directly from the mesothelial cells and does not migrate into the mesothelium from other organs.
The most common metastatic tumors that grow in the pleura derive from, in descending order:
breast
lung
ovary
stomach
large intestine
pancreas
thyroid
kidney
For the pericardial tumors from metastases, the most common originating organs are lung, breast and thyroid. In the peritoneum, the ovary, stomach, large intestine, pancreas and breast are the most common sources of metastatic tumors.

Mesothelioma Cancer Cells Types

Malignant mesothelioma is generally divided into three histological categories, or types of cells: epithelioid, sarcomatoid and biphasic mesothelioma. Within each of these mesothelioma cancer cell types, subtypes exist. Many mesothelioma patients display more than one cell type.

The diagnosis of mesothelioma cannot be specifically by lung x-rays or other types of imaging, because many different types of cancer can be present in the lungs. The images show only that a tumor may be present, but does not provide an indication of whether the tumor is mesothelioma. A biopsy must be performed where the mesothelioma cancer cell types are used to distinguish mesothelioma from other types of cancer, such as lung cancer.
Epithelioid Mesothelioma Cancer
Epithelioid mesothelioma is the most common cell type, constituting approximately 50% to 70% of all malignant mesothelioma. These cells are relatively uniform in shape and have a tubular pattern with a distinct cell nucleus. The individual cells are shaped like cubes or multi-sided boxes.
Because of the similarity between adenocarcinoma and mesothelioma cancer cells, they are often confused and mesothelioma can be misdiagnosed. Inspection of the cancer cells under high-powered microscopes and identification of unique characteristics of the chemical properties of the cells can help make the proper diagnosis. Learn more about epithelioid mesothelioma cancer.

Sarcomatoid Mesothelioma Cancer
Sarcomatoid mesothelioma is the least common type of mesothelioma cancer cell and accounts for approximately 10% to 15% of malignant mesothelioma. These cells typically have more of an oval, irregular shape and the nucleus of each cell is not as visible with a microscope as the epithelioid mesothelioma cancer cells. Because of the similarity of appearance, the sarcomatoid cancer cells can also easily be confused with the more typical sarcoma cancer cells. Learn more about sarcomatoid mesothelioma cancer.
Biphasic Mesothelioma Cancer
Approximately 20% to 40% of the mesothelioma cancer cells fall into the biphasic category, which is combination of the sarcomatoid and epithelioid types. The biphasic type can occur with the two types of cells intermixed continuously throughout the tumor, or with them in specific groupings. Transitional areas between the two cell types are often present. Learn more about biphasic mesothelioma cancer.
Prognosis Based on Cell Type
The mesothelioma cancer cell type does affect the prognosis. A study conducted on 167 patients showed that patients had the following mean survival times:
epithelioid
8.5 months
sarcomatoid
7 months
biphasic
6 months
Treatment options are very similar for patients with the different cell types.

Mesothelioma Trials

Mesothelioma is a relatively rare form of cancer linked to chronic asbestos exposure. There has been a sharp decline in asbestos exposure since the 1970s when asbestos use was halted for most applications. However, the incubation period for mesothelioma from initial exposure to asbestos to the onset of the disease varies from 20 to 50 years. As such, deaths related to this disease have risen recently and are expected to continue rising until the year 2020. This anticipated increase in incidence of mesothelioma has spurred considerable interest in clinical trials to develop better treatments for the deadly disease.

Mesothelioma Clinical Trials
Until recently, clinical trials for mesothelioma were difficult to conduct. The disease had a rapid onset and progression, leading to a relatively short survival period in which to conduct clinical trials. Also, there was a lack of basic understanding about the clinical biology of the disease and how the disease changed during progression.
Specific clinical measures were difficult to obtain in order to demonstrate the response to treatment. Recently, as part of the Alimta clinical trial, researchers developed new metrics that included factors other than just pleural thickening or abnormal breathing capability. A number of new clinical trials are now underway, many of them using these new measurement techniques. Hopefully these trials will lead to ways to stop or reverse the progression of mesothelioma.
Mesothelioma Trial Phases
Clinical trials for evaluating mesothelioma treatments are broken into four parts or phases. These Phases are described below (Source FDA).

Phase IResearchers evaluate a drug or treatment in a small group of people/patients (20 to 80) for the first time to evaluate a drug’s safety, determine the appropriate dosage range and identify side effects.
Phase IIResearchers treat a larger group of people/patients to determine if the drug treatment is effective and safe for the dosage levels determined in Phase I.
Phase IIIResearchers administer the drug or treatment to a large group of people/patients to confirm the effectiveness of the drug and evaluate the drug’s side effects. In this phase, the drug under evaluation will be compared to commonly used treatments. Additionally, researchers use Phase III trials to determine the proper protocol for the use of the drug when it is released for routine treatment.
Phase IVResearchers perform follow-up studies from Phase III, primarily to obtain information that can be used when marketing the drug, such as drug risks, benefits and optimum use.

Causes of Mesothelioma

Asbestos exposure is by far one of the most common causes of mesothelioma. Over 50% of the patients have a history of asbestos exposure. This exposure could occur while directly handling the fibrous material, or it could occur through just environmental exposure.
There are numerous documented cases where patients contracted the disease due to living close to the asbestos mines or by coming in contact with asbestos when some of the fibers became airborne. Persons most commonly afflicted include shipyard workers, construction workers, automobile mechanics (particularly those working on brake linings), insulation workers, pipe and heater installation and flooring workers and roofers.

Also, for those who have had asbestos exposure and who smoke, the risk becomes exaggerated. Studies show that asbestos workers who also smoke are 55 times more likely to die of mesothelioma than nonsmokers without asbestos exposure.
Erionite
Erionite is a mineral that has a long, thin rod-like amphiboles structure. Exposure to this mineral has been associated with increased incidence of mesothelioma. Erionite exposure has a high mortality rate due to mesothelioma in Anatolia, Turkey.
Exposure to asbestos is the primary cause for malignant mesothelioma in most patients. If you or a loved one has been exposed to asbestos, then you are at risk. There is no minimum level of exposure that is deemed safe. Insure that during your routine health care, you advise your doctor of previous asbestos exposure, particularly if you experience any chest pressure, shortness of breath, chest pain or coughing. While these symptoms do not indicate the presence of the disease, they are the most common symptoms and should be further investigated if you have had asbestos exposure.

An Introduction to Mesothelioma

Malignant mesothelioma is a rare form of cancer that affects the mesothelial cells of the serous membranes in the body. The most common form of mesothelioma, affecting the lining of the lung, is pleural mesothelioma. Two to three thousand new cases of malignant mesothelioma are diagnosed each year.

The mission of All About Malignant Mesothelioma is to provide a one-stop resource for comprehensive, up-to-date mesothelioma information. We cover the full scope of malignant mesothelioma issues including background, history, risk factors, diagnosis, and treatment. Please recommend the site to someone who may benefit from mesothelioma information.
Introduction to Malignant Mesothelioma
Malignant mesothelioma affects the lining or membranes of certain large cavities in the body. These cavities, called the serous cavities, house certain major organs in the body including the heart, lungs, abdomen and others. The membranes that surround these cavities are called the serous membranes. They serve to protect these major organs from the friction and abrasion that occur as the organs move against each other during typical daily functioning, such as breathing and heart beating. The serous membranes derive from specialized cells called mesothelial cells. These cells form to create the mesothelium, which is the major tissue layer of the serous membranes. Cancer that occurs in the mesothelium tissue is called mesothelioma.

Malignant mesothelioma takes on three forms:
Peritoneal mesothelioma, in the peritoneum or membrane surrounding the abdomen. A rare form of peritoneal mesothelioma can also affect the male testicles, because the lining around the scrotum is an extension of the peritoneum.
Pericardial mesothelioma, in the perdicardium or lining surrounding the heart.
Pleural mesothelioma, which is the most common form of malignant mesothelioma and affects the lining of the lung cavity.
All mesotheliomas are now considered to be malignant, or cancerous. They start as a localized tumor and spread rapidly to include most of the surrounding tissues and organs. Originally, fibrous cists and other non-cancerous growths that appeared in the serous membranes were thought to be mesotheliomas and were termed "benign fibrous mesothelioma" and "multicystic mesothelioma." These conditions are now known not to originate in the mesothelial cells, but other cells within the serous membranes. These conditions are typically localized, non-cancerous and do not spread rapidly.
Etiology of Malignant Mesothelioma
Most cases of malignant mesothelioma are associated with a previous exposure to fibrous minerals, of which asbestos is the most important. There is now indisputable evidence of the role of these fibers in the development of this disease. This has been demonstrated in animal experiments and many other experiments. Not everyone who is exposed to asbestos fibers has developed malignant mesothelioma, suggesting that other factors may also be involved.
Although malignant mesothelioma is rare, it is a serious, deadly disease. It is often in the advanced stages when it is detected, so the outlook for the patients is not as good as it is for the cancers that are detected earlier. The average survival time after detection is 1 to 2 years. This survival time also depends on the type of mesothelioma.