Lung Cancer Disease

What is Lung Cancer?



Also called: Bronchogenic carcinoma

Lung cancer is a malignant (cancerous) tumor that starts from cells of the lung.

The lungs are a pair of sponge-like organs found in the chest that take in oxygen when we breathe in and get rid of carbon dioxide when we breathe out. The right lung is a bit larger than the left lung, which is smaller to accommodate for the size of the heart on the left side of the body. The right lung has three sections, called lobes, and the left lung has two.

Lung cancer is the rapid growth of abnormal cells in the lung. It can start anywhere in the lungs and affect any part of the respiratory system.

Lung cancer is the leading cause of cancer deaths in both men and women. Fewer than half of the people who develop lung cancer live 1 more year. And only 15% of people who develop lung cancer live for 5 more years.

Type of Lung Cancer



Lung cancer is commonly divided into two types:

1. Small Cell Lung Cancer (SCLC). Small cell lung cancer spreads early in the course of the disease and occurs almost exclusively in smokers. Surgical removal usually isn't an option for this type of cancer; instead, it's best treated with chemotherapy and radiation. Even so, the five-year survival rate for small cell lung cancer is very low.

• Non-Small Cell Lung Cancer (NSCLC). Non-small cell lung cancer, which is more common, accounts for more than 75 percent of lung cancers. If caught early when it's confined to a small area, it often can be removed surgically. There are four major categories of non-small cell lung cancer:
• Squamous cell carcinoma: is a cancer that begins in squamous cells, which are thin, flat cells found in the passages of the respiratory and digestive tracts as well as in the surface of the skin and the lining of the hollow organs of the body. This type of NSCLC is linked to a history of smoking and usually found centrally, near a bronchus. It is also called epidermoid carcinoma. This cancer forms in cells lining the airways. It's the most common type in men.
• Adenocarcinoma: This type of cancer usually begins in the mucous-producing cells of the lung. It's the most common type in women and in people who have never smoked or were exposed to secondhand smoke.
• Large cell carcinoma: is a type of lung cancer in which the cells are large and look abnormal when viewed under a microscope. It can be found in any part of the lung and tends to grow and spread rapidly. This type of cancer originates in the peripheral part of the lungs.
• Bronchoaveolar carcinoma: This uncommon type of non-small cell lung cancer tends to grow more slowly than other forms of the disease. It occurs more often in smokers than in nonsmokers and tends to arise in more than one location at the same time.

What causes lung cancer?

Although smoking is by far the leading risk factor for lung cancer, it is known that there are several other risk factors linked to the disease. Some of the risk factors for lung cancer are discussed below:

1. Smoking

Tobacco smoking is believed to be responsible for 80 percent of all cases of lung cancer. The risk of lung cancer increases with the length of time a person has been smoking, the number of packs per day smoked, and how deeply the smoke is inhaled. However, if a person quits smoking before lung cancer develops, the lung tissue slowly returns to normal, which lowers the risk of lung cancer.

Some people think that smoking cigars and pipes is less harmful than smoking cigarettes. However, research has shown that cigar and pipe smoking are almost as likely to cause lung cancer as cigarette smoking. Even cigar and pipe smokers who do not inhale are at increased risk for lung, mouth and other types of cancers.

Secondhand smoke, also called environmental tobacco smoke, describes the smoke in the air when someone else smokes. Exposure to secondhand smoke is called involuntary or passive smoking and increases lung cancer risk. For example, nonsmoking spouses of smokers and people exposed to tobacco smoke in the workplace are more likely to get lung cancer.

2. Asbestos

Asbestos is any of several minerals that occur naturally as fibers. These fibers tend to break easily into particles, which can float in the air and become inhaled, where they can lodge in the lungs, damaging cells and increasing the risk for lung cancer. Formerly used as fireproof insulating materials, asbestos is rarely used today in the workplace or in home products, as it has since been implicated as a cause of certain cancers.

Workers who have been exposed to large amounts of asbestos — such as those in industries like shipbuilding, insulation work, and asbestos mining and manufacturing — have a higher risk of getting lung cancer. The risk of lung cancer is even higher among asbestos workers who also smoke.

3. Radon

Radon is an invisible, odorless and tasteless radioactive gas that occurs naturally in soil and rock. It can cause damage to the lungs that may lead to lung cancer. People who work in mines may be exposed to radon; occasionally, radon can also accumulate indoors. Radon levels in homes may be measured by a kit found in most hardware stores.

4. Marijuana

Many of the carcinogens found in tobacco are also found in marijuana, which actually has more tar than regular cigarettes. Research suggests that marijuana may also cause cancers of the mouth and throat.

5. Lung diseases

Certain lung diseases, such as tuberculosis and some types of pneumonia, often leave scars on the lung that can increase the risk of developing lung cancer.

6. Personal and family history

A person who has had lung cancer once is at increased risk for developing a second lung cancer. Siblings and children of people who have had lung cancer may also have a slightly higher risk.

What are the symptoms of lung cancer?

Because most lung cancers do not cause any symptoms until they have spread, only about 15 percent of lung cancers are found in the early stages. When lung cancer is found early, it is often as a result of a chest X-ray, CT scan or other test that was being done for another reason. Symptoms of lung cancer may include:

• A cough that does not go away and gets worse over time.
• Constant chest pain, often made worse by deep breathing.
• Hoarseness.
• Weight loss and loss of appetite.
• Coughing up blood.
• Shortness of breath.
• Recurring infections such as bronchitis and pneumonia.
• New onset of wheezing.
• Swelling of the neck and face.
  

Remember that these symptoms may be caused by conditions other than lung cancer. It is important to check with a doctor.

Diagnostic Tests for Lung Cancer:



If there is any reason to suspect lung cancer, the doctor will take a medical history and conduct a physical exam. The doctor may also order a chest X-ray and other tests. If lung cancer is suspected, sputum cytology (the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs) is a simple test that may be useful in detecting lung cancer.

To confirm the presence of lung cancer, the doctor must examine tissue from the lung. A biopsy — the removal of a small sample of tissue for examination under a microscope by a pathologist — can show whether a person has cancer. A number of procedures may be used to obtain this tissue:

* Bronchoscopy: The doctor puts a bronchoscope (a thin, lighted tube) into the mouth or nose and down through the windpipe and into the bronchi. This test can help find tumors or it can be used to take samples of tissue or fluids to see if cancer cells are present.

* Needle aspiration: A needle is inserted through the chest into the tumor to remove a sample of tissue.

* Thoracentesis: Using a needle, the doctor removes a sample of the fluid that surrounds the lungs. This test is done to check whether fluid around the lungs is caused by cancer or by a benign condition such as heart failure or an infection.

* Thoracotomy: Surgery to open the chest is sometimes needed to diagnose lung cancer. This procedure is a major operation performed in a hospital.

If the diagnosis is cancer, the doctor will conduct additional tests to determine the stage (or extent) of the disease (stages of lung cancer are discussed later). Some tests used to determine the cancer stage include:

* Computed tomography (CT) scan: A CT scan is an X-ray procedure in which the X-ray beam moves around the body, taking pictures from different angles. These images are combined by a computer to produce a detailed cross-sectional picture of the inside of the body.

* Magnetic resonance imaging (MRI): MRI uses large magnets and radio waves to produce computer-generated cross-sectional pictures of internal organs.

* Radionuclide scanning: Scanning can show whether cancer has spread to other organs, such as the liver. The patient swallows or receives an injection of a mildly radioactive substance. A machine (scanner) measures and records the level of radioactivity in certain organs to reveal abnormal areas.

* Bone scan: A bone scan is a type of radionuclide scanning that can show whether cancer has spread to the bones.

* Mediastinoscopy: A mediastinoscopy can help show whether the cancer has spread to the lymph nodes in the chest. With the patient asleep, tissue samples are taken from the lymph nodes along the windpipe through a small hole cut into the neck. Examining the tissue under a microscope can show if cancer cells are present.

* Bone marrow biopsy: A needle is used to remove a small piece of bone, usually from the back of the hipbone, and the sample is checked for cancer cells.

* Blood tests: Certain blood tests are often done to help see if the lung cancer has spread to the liver or bones.

Lung Cancer Treatment

Lung cancer treatment depends on the type and stage of cancer, as well as the overall health of the patient.

Treatment may include surgery to remove the cancer, radiation therapy, or medications (chemotherapy). Treatment for non–small and small cell cancer may be different.

Lung cancer treatment may include one or more of the following therapies:

1. Surgery

Surgery is taking out the cancer. Surgery is the most effective treatment for early-stage non–small cell lung cancers (stages I and II). In some cases, only the portion of the lung that contains the tumor is removed. In others, one lobe or even the entire lung may be taken. Surgery to remove all or part of a lung often involves opening one side of the chest, a procedure called a thoracotomy.

Operations to treat lung cancer include:

• Wedge resection: In this operation, the doctor removes only the section of the lung that contains the tumor along with a margin of normal tissue.
• Lobectomy: The most common type of surgery, lobectomy involves removing an entire lobe of one lung.
• Pneumonectomy: In this operation, an entire lung is removed. Because pneumonectomy will decrease lung function considerably, as well as lead to other complications, it's performed only when absolutely necessary and then only if the patient breathing capacity is sufficient to allow breathing with a single lung.
  

Lung function studies and a lung scan are often done before surgery to predict whether the patient will have enough remaining lung function after surgery to live a fairly normal life.

2. Radiation therapy

Radiation therapy uses high-dose X-rays to kill cancer cells. Radiation therapy is often used in combination with surgery or chemotherapy or both. Radiation following surgery for stages IIA, IIB, and IIIA (with lymph node involvement) may reduce the risk of cancer returning in the chest.

The way in which radiation is delivered depends on the type and stage of the cancer being treated. Radiation therapy may be given before, during or after chemotherapy. In all cases, however, the goal of treatment is to destroy cancer cells while harming as little normal tissue as possible.

Small cell lung cancer often spreads to the brain. For that reason, the doctor may sometimes recommend brain radiation therapy to prevent cancer from metastasizing to that part of the body or to eliminate micrometastases that aren't yet detectable with imaging studies. Brain radiation therapy can cause short-term memory problems, fatigue, nausea and other serious side effects.

3. Chemotherapy

Because most small cell lung cancers have spread beyond the lungs by the time they're discovered, an operation usually isn't a treatment option. Instead the most effective treatment is chemotherapy, either alone or in combination with radiation therapy.

Chemotherapy uses medications or drugs to kill cancer cells. Chemotherapy is the most effective treatment for small cell lung cancer, but it is only a cure in a small number of people. Chemotherapy has been shown to improve survival in non-small lung cancer when it is given after surgery for stages IB, IIA, IIB, and IIIA. It may also be used to treat more advanced stages (stages III and IV) of non–small cell lung cancer.

In cases of small cell lung cancer, chemotherapy may be used to shrink the cancer, to slow the cancer's growth, to prevent it from spreading further, or to relieve symptoms and make the patient more comfortable (palliative care). A combination of drugs usually is given in a series of treatments over a period of weeks or months, with breaks in between so that the body can recover. Even so, because the drugs damage healthy cells along with malignant ones, they can cause serious side effects.

4. Targeted therapy

Targeted therapies use medications or antibodies to block growth factors that allow some cancers to grow. At this time, targeted therapies are used for advanced stages.

resource: Cancer Info Guide

Staging of Lung Cancer:

TNM staging is a process to measure how advanced the cancer is. The following three factors are considered:

* Tumor - size and location
* Node - lymph node involvement
* Metastasis - has the cancer spread

1. Small cell lung cancer staging:

Limited stage : The cancer is only in one lung and in lymph nodes on the same side of the chest.

Extensive stage : The cancer has spread to the other lung, to lymph nodes on the other side of the chest, or to distant organs. Many doctors consider cancer that has spread to the fluid around the lung to be extensive stage as well.

2. Non-small cell lung cancer staging:

Stage 0 : The cancer is limited to the lung and is found in a few layers of cells only. It has not grown through the top lining of the lung. Stage 0 is also called carcinoma in situ.

Stage : The cancer is in the lung only, with normal tissue around the tumor. Stage I is divided into stages IA and IB, based on the size of the tumor.

Stage II : The cancer has spread to nearby lymph nodes or to the chest wall (the ribs and muscles that make up the area of the body between the neck and abdomen); the diaphragm (thin muscle below the lungs and heart that separates the chest from the abdomen); the mediastinal pleura (thin membrane that covers the outside of the lungs in the area near the heart); or the parietal pericardium (outer layer of tissue that surrounds the heart). Stage II is divided into stage IIA and stage IIB, based on the size of the tumor and whether it has spread to the lymph nodes.

Stage III : The cancer has either:
* Spread to the lymph nodes in the mediastinum (middle area between the lungs that contains the heart, major blood vessels and other structures);or
* Spread to the lymph nodes on the opposite side of the chest or in the lower neck.

Stage III is divided into stage IIIA (which is sometimes treated with surgery) and stage IIIB (which is rarely treated with surgery).

Stage IV : The cancer has spread to other parts of the body or to another lobe of the lungs.

Resource:
National Cancer Institute
MEDLINEplus Health Information
CancerGuide

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Asbestosis - Pulmonary Asbestosis Disease

What is Asbestosis?

Asbestosis is a chronic inflammatory lung disease that occurs due to long- term exposure to asbestos fibres .

Asbestosis is a breathing disorder caused by inhaling asbestos fibers. Prolonged accumulation of these fibers in your lungs can lead to scarring of lung tissue and diminished breathing capacity. Because many other diseases also lead to lung scarring, other causes must be excluded first when a patient is found to have lung scarring (pulmonary fibrosis).

Asbestosis particularly affects the parenchymatous tissues of the lungs and has gained increased significance due to its link to mesothelioma and to other forms of lung and laryngeal cancer. Asbestosis is also frequently associated with Chronic Obstructive Pulmonary Disease (COPD).

Asbestosis, as a medical problem, was recognized early in the 20th century. A few decades later studies established asbestosis as a predisposing factor for bronchogenic carcinoma and malignant mesothelioma. The developed countries have started recognizing the harmful effects of asbestos and have replaced it with synthetic metal fibres. Legislations have been passed globally to curtail its use in industries.

Patients with particular x-ray findings or biopsy results must also have a remote history of asbestos exposure and a characteristically delayed development of the condition in considering asbestosis as a diagnosis. Smoking appears to increase the frequency and/or the rate of progression of asbestosis, possibly by preventing the efficient elimination of inhaled fibers from the airways.

What are symptoms and signs of asbestosis?

The clinical symptoms usually include slowly progressing shortness of breath and cough, often 20 to 40 years after exposure to asbestos. Breathlessness advances throughout the disease, even without further asbestos inhalation. In the absence of cigarette smoking, sputum (mucus coughed up from the lungs) production and wheezing are uncommon. The exception is workers who have been exposed to very high concentrations of asbestos fibers. Those workers may also develop symptoms as soon as 10 years after exposure. Other indications of asbestosis include abnormal lung sounds on examination, changes in the ends of the fingers and toes ("clubbing"), a blue tinge to the fingers or lips ("cyanosis"), and failure of the right side of the heart ("cor pulmonale"). Asbestosis can be a progressive disease even after exposure to asbestos has stopped.

Signs and symptoms develop when damage and scarring caused by the asbestos fibers lead to stiffness in your lung tissue so that your lungs can't contract and expand normally (a form of pulmonary fibrosis). Once exposure to asbestos is stopped, however, the fibrosis does not progress.

Some asbestosis symptoms include:

* Shortness of breath, initially only with exertion, but eventually even while resting
* Decreased tolerance for physical activity
* Coughing
* Chest pain
* Finger clubbing in some cases

Although most of these signs and symptoms are similar to those of other breathing disorders, such as asthma, the way in which they develop is different. In asbestosis the effects of the disease are insidious, occurring over months and years.

Diagnosing Asbestosis





The diagnosis of asbestosis is made when there is a history of asbestos exposure and positive results from a clinical exam. There is a well-defined latency period of approximately 20 years or more between the initial exposure to asbestos and the development of asbestos related calcification and scarring.

Asbestosis can be diagnosed by the following tests:

• Chest X-ray- irregular opacities in the lower lobes, heart border becomes shaggy. In the late stages of disease, there is a honey-comb likeness and volume loss. X rays can show shadows or spots on the lungs or an indistinct or shaggy outline of the heart that suggests the presence of asbestosis.
• CT scan- scarring and thickening can be seen on the chest x-ray and CT, but the CT scan can detect calcifications around the lung (typical of asbestosis) more often. It is considered the most accurate means for detecting asbestos related abnormalities.
• PFTs- pulmonary function testing is used to test for loss of lung volume, and for the impairment of movement of oxygen across the air sacs. Pulmonary function tests can be used to assess a patient's ability to inhale and exhale, and a computed tomography scan (CT) of the lungs can show flat, raised patches associated with advanced asbestosis.
• Blood tests are used to measure concentrations of oxygen and carbon dioxide.

Complications

The severity of asbestosis is generally related to the amount and duration of exposure to asbestos. Effects of the disease may be so mild as to cause almost no symptoms. Or the condition may create such a reduced flow of oxygen as to be disabling or even fatal. Asbestosis may lead to the following conditions:

• High blood pressure in your lungs. Asbestosis-related scar tissue may eventually compress or obliterate your lungs' small blood vessels, causing high blood pressure in your lungs' arteries (pulmonary hypertension).
• Heart problems. Pulmonary hypertension can lead to enlargement and failure of your heart's right ventricle (cor pulmonale). Your heart consists of four chambers — two upper chambers called atria and two lower chambers called ventricles. Your right ventricle assists in pumping oxygen-poor blood from your organs and tissues to your lungs, where your blood receives a new boost of oxygen. As your pulmonary arteries narrow, your heart's right ventricle must work harder to pump blood through the lungs. Initially, the heart tries to compensate by thickening its walls and dilating the right ventricle to increase the amount of blood it can hold. But this measure only works temporarily, and eventually — after a period of a few years — the right ventricle weakens and fails from the extra strain.
• Lung cancer. If you smoke and have asbestosis, your chances of developing lung cancer increase greatly, especially if you smoke more than a pack a day. Tobacco smoke and asbestos both contribute to each other's cancer-causing (carcinogenic) effects, so that the combination of both risk factors together is more dangerous than the effects of either risk factor alone.
• Other lung damage. Exposure to asbestos can lead to other health complications including changes in the thin membranes covering your lungs and lining your chest cavity (pleural membranes). Pleural changes may be the first signs of asbestos exposure and may include pleural thickening, the formation of calcium deposits in the pleura (plaques), and an abnormal accumulation of fluid between the membranes (pleural effusion). Pleural effusion itself is benign and doesn't increase your risk of asbestosis or malignant mesothelioma.
• Other cancer. Prolonged exposure — 20 years or more — to asbestos can also lead to malignant mesothelioma. Diagnosis and treatment of this cancer is often difficult. Malignant mesothelioma may occur even many years after exposure has stopped.
  

How is asbestosis treated?

Patients with asbestosis, like others with chronic lung disease, are at a higher risk of serious infection, low oxygen levels in the blood, and heart failure. These patients also may not recover as quickly from viral and bacterial infections. In addition, they may be at increased risk for certain fungal and unusual infections that take advantage of diseased or scarred lung tissue. The medical management of these patients should focus special attention on preventing and rapidly treating these infections. Flu and pneumococcal vaccinations are a part of routine care for these patients. There is, however, no treatment or cure for asbestosis. In particular, steroid and immune-based therapies have not been shown to benefit these patients.

There's no treatment to reverse the effects of asbestos on the alveoli. Treatment focuses on preventing progression of the disease and relieving symptoms. The most important factor in keeping the condition from worsening is to eliminate exposure to asbestos. For most people, scarring of lung tissue doesn't begin or progress once exposure has ended.

The following may be components of asbestosis treatment:

• Smoking cessation. If you smoke, it's important to stop, particularly because of the extremely heightened risk of lung cancer. In addition, smoking may cause emphysema, which further reduces your lung reserves.
• Vaccinations. Because of your impaired lung condition, treat a cold or a bout of the flu promptly to avoid complications. Your doctor may advise you to receive flu and pneumonia vaccines.
• Medications. The complication of pulmonary hypertension is often treated with medications to expand or relax blood vessels, and blood-thinning medications to prevent blood clots from forming and obstructing narrowed vessels.
  

To ease difficulty breathing, your doctor may prescribe supplemental oxygen or drain fluid from around your lungs, if necessary. Occasionally, severe cases of asbestosis may be treated with lung transplantation.

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Asbestos Disease | Types of Asbestos Disease

Asbestosis scaring of the lung tissue Mesothelioma nodular cancer of the plural lining of the lung Lung Cancer Note: smoking greatly increases risk - 50 to 90 times

The most common forms of asbestos disease are pleural plaques, asbestosis, lung cancer, and mesothelioma.

Asbestosis

Asbestosis is a disease which is characterized by pulmonary fibrosis, a progressive scarring of the lungs caused by the accumulation of asbestos fibers. Asbestosis is associated exclusively with chronic, occupational exposure. The build up of scar tissue interferes with oxygen uptake through the lungs and can lead to respiratory and heart failure. Often, asbestosis is a progressive disease, even in the absence of continued exposure. Symptoms include shortness of breath, cough, fatigue, and vague feelings of sickness. When the fibrosis worsens, shortness of breath occurs even at rest.

Pleural Plaques

Pleural plaques and pleural calcification are markers of exposure and may develop 10 to 20 years after initial exposure. Plaques are opaque patches visible on chest x-rays that consist of dense strands of connective tissue surrounded by cells. All commercial types of asbestos induce plaques. Plaques can occur even when fibrosis is absent and do not seem to reflect the severity of pulmonary disease.

Lung Cancer

Of all the diseases related to asbestos exposure, lung cancer has been responsible for over half of the excess deaths resulting from occupational exposure. Although tissues and cells react to the presence of asbestos immediately, detectable symptoms take years, or more often decades, to manifest themselves. Asbestos-induced lung cancer may not show up on x-rays for twenty years or more after the exposure began. This delay between exposure and onset is referred to as the "latency period". Even in cases of prolonged heavy exposure, abnormalities commonly appear on x-rays only after ten or more years following exposure.

Mesothelioma

Mesothelioma is rare or nonexistent in non-asbestos exposed populations but is becoming more common among asbestos-exposed individuals.

Mesothelioma is a cancer of the lining of the lungs and not a cancer that occurs inside the lung. Mesothelioma causes the cells of the mesothelium to become abnormal and infinitely reproduce.

A normal mesothelium cell (or any cell for that matter) can only reproduce a certain amount of times. This keeps certain cells from invading other cells. Cancer occurs when those cells become mutated and their limits are removed, allowing them to reproduce uncontrollably. These abnormal cells then form a lump that is known as a tumor. In a benign tumor the abnormal cells do not spread into surrounding areas, but malignant tumors do have the ability to spread. If the tumor is left untreated then it may spread and destroy the neighboring tissue. Sometimes cells can even break off the original tumor and spread to other organs and tissue through the bloodstream or the lympathic system. The lympathic system is part of the immune system. It is a complex system that includes the bone marrow, the thymus and the spleen, and lymph nodes throughout the body that are connected by a network of lympathic vessels. When the cancer cells reach a new site they may continue to divide and form a new tumor, which is referred to as a secondary tumor or a metastasis.

Mesothelial cells line the chest cavity, the abdominal cavity, and the cavity around the heart. They also cover the outer surface of most internal organs. The tissue that is formed by these mesothelial cells is called mesothelium. Mesothelium helps protect the organs by producing a lubricating fluid that lets organs move around. This fluid makes it easier for the lungs to expand and move around inside the chest during breathing. The mesothelium in the chest is called the pleura and the mesothelium around the abdomen is known as the peritoneum. The mesothelium around the heart (or the pericardial cavity, a sac like space around the heart) is called the pericardium.

The asbestos disease mesothelioma has a long latency period, where it is present but not evident or active. The disease can lie dormant for ten to sixty years after being exposed to asbestos. Because of this, it is often hard to determine the cause of mesothelioma.

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