Lung Cancer

What is Lung Cancer

2010-01-01T23:09:00.001-08:00

Lung cancer is a disease of uncontrolled cell growth in tissues of the lung. This growth may lead to metastasis, which is the invasion of adjacent tissue and infiltration beyond the lungs. The vast majority of primary lung cancers are carcinomas of the lung, derived from epithelial cells. Lung cancer, the most common cause of cancer-related death in men and the second most common in women (after breast cancer), is responsible for 1.3 million deaths worldwide annually. The most common symptoms are shortness of breath, coughing (including coughing up blood), and weight loss.

Symptoms of Lung Cancer

2010-01-01T23:08:00.001-08:00

Signs and symptoms
Symptoms that suggest lung cancer include:[28]
dyspnea (shortness of breath)
hemoptysis (coughing up blood)
chronic coughing or change in regular coughing pattern
wheezing
chest pain or pain in the abdomen
cachexia (weight loss), fatigue, and loss of appetite
dysphonia (hoarse voice)
clubbing of the fingernails (uncommon)
dysphagia (difficulty swallowing).

Medical Treatment

2010-01-01T22:48:00.001-08:00

Chemotherapy and radiation therapy

Chemotherapy and radiation may lead to a cure in a small number of patients. These therapies result in shrinking of the tumor and are known to prolong life for extended periods in most patients.
Chemotherapy and radiation are very effective at relieving symptoms.
Inoperable NSCLCs are treated with chemotherapy or a combination of chemotherapy and radiation.
If SCLC is in an early stage (confined to the thorax), the standard of care is chemotherapy and radiation therapy given at the same time.
In later stages (spread outside of the thorax), SCLC is treated with chemotherapy and palliative radiation therapy to areas where metastases may be present.
The brain is sometimes treated with radiation even if no tumor is present there. Called prophylactic cranial irradiation (PCI), this therapy may prevent a tumor from forming. PCI is not suitable for all patients, however, and side effects may occur.
Limited SCLC (has not spread outside the chest cavity) has an 80%-90% rate of response to combination chemotherapy and radiation therapy. Remission (no cancer detected by physical examination or x-ray studies) occurs in 50%-60% of cases.
Of all cases of advanced-stage lung cancer (spread outside the chest cavity), approximately 50%-60% of SCLC and 15%-40% of NSCLC will go in to remission with chemotherapy.
If relapse occurs, a different type of chemotherapy regimen may offer symptom relief and modest survival benefit.
Even with an initially favorable response to treatment, SCLC tends to relapse within one to two years in most patients, particularly in those with extensive disease.
Recent research has shown benefits of adjuvant chemotherapy in early stage NSCLC in preventing or delaying recurrence of the tumor, even after surgery that is felt to be successful at removing cancer.
Chemotherapy uses chemicals that travel through the bloodstream. It affects both cancerous and healthy cells. This accounts for the many well-known side effects of chemotherapy, including nausea and vomiting, hair loss, skin problems, mouth sores, and fatigue.
Radiation therapy does not affect cells throughout the body the way chemotherapy does. However, it does affect healthy tissues overlying or directly adjacent to the tumor. To a certain extent, the side effects of radiation depend on which part of the body is targeted with radiation.
Based on recent clinical trial data, chemotherapy has been found to be beneficial for all stages of non-small cell lung cancer, including stage I or II. People with lung cancer should be referred to an oncologist for discussion of options.

Reference:/www.emedicinehealth.com/lung_cancer/page6_em.htm#Medical Treatment

How can lung cancer be prevented?

2010-01-01T22:45:00.001-08:00

Smoking cessation is the most important measure that can prevent lung cancer. Many products, such as nicotine gum, nicotine sprays, or nicotine inhalers, may be helpful to people trying to quit smoking. Minimizing exposure to passive smoking is also an effective preventive measure. Using a home radon test kit can identify and allow correction of increased radon levels in the home, which can also cause lung cancers. Methods that allow early detection of cancers, such as the helical low-dose CT scan, may also be of value in the identification of small cancers that can be cured by surgical resection and prevention of widespread, incurable metastatic cancer.
reference:/www.medicinenet.com/lung_cancer/page8.htm#tocj

Lung Cancer in Women

2010-01-01T09:18:00.001-08:00

Lung cancer in women differs from lung cancer in men in many ways. Yet, despite obvious differences in our appearance, we tend to lump men and women together when talking about lung cancer. This is unfortunate, since the causes, response to various treatments, survival rate, and even symptoms to watch for differ. What are some facts about lung cancer in women?

Statistics About Lung Cancer in Women

Lung cancer is the leading cause of cancer deaths in women, killing more women each year than breast cancer, uterine cancer, and ovarian cancer combined. While smoking is the number one cause, 20% of these women have never touched a cigarette. Once considered a “man’s disease,” lung cancer is no longer discriminatory. In 2005, the last year for which we have statistics, 82,271 women (vs 107,416 men) were diagnosed with lung cancer, and 69,078 (vs 90,139 men) died.
While lung cancer diagnoses decreased each year from 1991-2005 for men, the incidence increased 0.5% each year for women. The reason for this is not completely clear.
Lung cancer in women occurs at a slightly younger age, and almost half of lung cancers in people under 50 occur in women.

Causes of Lung Cancer in Women

Even though smoking is the number one cause of lung cancer in women, a higher percentage of women who develop lung cancer are life-long non-smokers. Some of the causes may include exposure to radon in our homes, secondhand smoke, other environmental and occupational exposures, or a genetic predisposition. Recent studies suggest infection with the human papilloma virus (HPV) may also play a role.
reference:http://lungcancer.about.com/od/whatislungcancer/a/lungcancerwomen.htm

How is lung cancer treated?

2010-01-01T09:13:00.001-08:00

Treatment for lung cancer can involve surgical removal of the cancer, chemotherapy, or radiation therapy, as well as combinations of these treatments. The decision about which treatments will be appropriate for a given individual must take into account the localization and extent of the tumor as well as the overall health status of the patient.
As with other cancers, therapy may be prescribed that is intended to be curative (removal or eradication of a cancer) or palliative (measures that are unable to cure a cancer but can reduce pain and suffering). More than one type of therapy may be prescribed. In such cases, the therapy that is added to enhance the effects of the primary therapy is referred to as adjuvant therapy. An example of adjuvant therapy is chemotherapy or radiotherapy administered after surgical removal of a tumor in order to be certain that all tumor cells are killed.
Surgery: Surgical removal of the tumor is generally performed for limited-stage (stage I or sometimes stage II) NSCLC and is the treatment of choice for cancer that has not spread beyond the lung. About 10%-35% of lung cancers can be removed surgically, but removal does not always result in a cure, since the tumors may already have spread and can recur at a later time. Among people who have an isolated, slow-growing lung cancer removed, 25%-40% are still alive five years after diagnosis. Surgery may not be possible if the cancer is too close to the trachea or if the person has other serious conditions (such as severe heart or lung disease) that would limit their ability to tolerate an operation. Surgery is less often performed with SCLC because these tumors are less likely to be localized to one area that can be removed.
The surgical procedure chosen depends upon the size and location of the tumor. Surgeons must open the chest wall and may perform a wedge resection of the lung (removal of a portion of one lobe), a lobectomy (removal of one lobe), or a pneumonectomy (removal of an entire lung). Sometimes lymph nodes in the region of the lungs are also removed (lymphadenectomy). Surgery for lung cancer is a major surgical procedure that requires general anesthesia, hospitalization, and follow-up care for weeks to months. Following the surgical procedure, patients may experience difficulty breathing, shortness of breath, pain, and weakness. The risks of surgery include complications due to bleeding, infection, and complications of general anesthesia.
Radiation: Radiation therapy may be employed as a treatment for both NSCLC and SCLC. Radiation therapy uses high-energy X-rays or other types of radiation to kill dividing cancer cells. Radiation therapy may be given as curative therapy, palliative therapy (using lower doses of radiation than with curative regimens), or as adjuvant therapy in combination with surgery or chemotherapy. The radiation is either delivered externally, by using a machine that directs radiation toward the cancer, or internally through placement of radioactive substances in sealed containers within the area of the body where the tumor is localized. Brachytherapy is a term used to describe the use of a small pellet of radioactive material placed directly into the cancer or into the airway next to the cancer. This is usually done through a bronchoscope.
Radiation therapy can be given if a person refuses surgery, if a tumor has spread to areas such as the lymph nodes or trachea making surgical removal impossible, or if a person has other conditions that make them too ill to undergo major surgery. Radiation therapy generally only shrinks a tumor or limits its growth when given as a sole therapy, yet in 10%-15% of people it leads to long-term remission and palliation of the cancer. Combining radiation therapy with chemotherapy can further increase the chances of survival when chemotherapy is administered. External radiation therapy can generally be carried out on an outpatient basis, while internal radiation therapy requires a brief hospitalization. A person who has severe lung disease in addition to a lung cancer may not be able to receive radiotherapy to the lung. A type of external radiation therapy called the "gamma knife" is sometimes used to treat single brain metastases. In this procedure, multiple beams of radiation are focused on the tumor over a few minutes to hours while the head is held in place by a rigid frame.
For external radiation therapy, a process called simulation is necessary prior to treatment. Using CT scans, computers, and precise measurements, simulation maps out the exact location where the radiation will be delivered, called the treatment field or port. This process usually takes 30 minutes to two hours. The external radiation treatment itself generally is done over four or five days a week for several weeks.
Radiation therapy does not carry the risks of major surgery, but it can have unpleasant side effects including fatigue and lack of energy. A reduced white blood cell count (rendering a person more susceptible to infection) and low blood platelet levels (making blood clotting more difficult) can also occur with radiation therapy. If the digestive organs are in the field exposed to radiation, patients may experience nausea, vomiting, or diarrhea. Radiation therapy can irritate the skin in the area that is treated, but this irritation generally improves with time after treatment has ended.
Chemotherapy: Both NSCLC and SCLC may be treated with chemotherapy. Chemotherapy refers to the administration of drugs that stop the growth of cancer cells by killing them or preventing them from dividing. Chemotherapy may be given alone, as an adjuvant to surgical therapy, or in combination with radiotherapy. While a number of chemotherapeutic drugs have been developed, the class of drugs known as the platinum-based drugs have been the most effective in treatment of lung cancers.
Chemotherapy is the treatment of choice for most SCLC, since these tumors are generally widespread in the body when they are diagnosed. Only half of people who have SCLC survive for four months without chemotherapy. With chemotherapy, their survival time is increased up to four- to fivefold. Chemotherapy alone is not particularly effective in treating NSCLC, but when NSCLC have metastasized, it can prolong survival in many cases.
Chemotherapy may be given as pills, as an intravenous infusion, or as a combination of the two. Chemotherapy treatments are usually given in an outpatient setting. A combination of drugs is given in a series of treatments, called cycles, over a period of weeks to months, with breaks in between cycles. Unfortunately, the drugs used in chemotherapy also kill normally dividing cells in the body, resulting in unpleasant side effects. Damage to blood cells can result in increased susceptibility to infections and difficulties with blood clotting (bleeding or bruising easily). Other side effects include fatigue, weight loss, hair loss, nausea, vomiting, diarrhea, and mouth sores. The side effects of chemotherapy vary according to the dosage and combination of drugs used and may also vary from individual to individual. Medications have been developed that can treat or prevent many of the side effects of chemotherapy. The side effects generally disappear during the recovery phase of the treatment or after its completion.
Brain prophylactic radiation: SCLC often spreads to the brain. Sometimes people with SCLC that is responding well to treatment are treated with radiation therapy to the head to treat very early spread to the brain (called micrometastasis) that is not yet detectable with CT or MRI scans and has not yet produced symptoms. Brain radiation therapy can cause short-term memory problems, fatigue, nausea, and other side effects.
Treatment of recurrence: Lung cancer that has returned following treatment with surgery, chemotherapy, and/or radiation therapy is called recurrent or relapsed. If a recurrent cancer is confined to one site in the lung, it may be treated with surgery. Relapsed tumors generally do not respond to the chemotherapeutic drugs that were previously administered. Since platinum-based drugs are generally used in initial chemotherapy of lung cancers, these agents are not useful in most cases of recurrence. A type of chemotherapy referred to as second-line chemotherapy is used to treat recurrent cancers that have previously been treated with chemotherapy, and a number of second-line chemotherapeutic regimens have been proven effective at prolonging survival. People with recurrent lung cancer who are well enough to tolerate therapy are also good candidates for experimental therapies (see below), including clinical trials.
Targeted therapy: One alternative to standard chemotherapy is the drug erlotinib (Tarceva) which may be used in patients with NSCLC who are no longer responding to chemotherapy. It is a so-called targeted drug, a drug that more specifically targets cancer cells, resulting in less damage to normal cells. Erlotinib targets a protein called the epidermal growth factor receptor (EGFR) that helps cells to divide. This protein is found at abnormally high levels on the surface of some types of cancer cells, including many cases of non-small cell lung cancer. Erlotinib is taken by mouth in pill form.
Other attempts at targeted therapy include drugs known as antiangiogenesis drugs, which block the development of new blood vessels within a cancer. Without adequate blood vessels to supply oxygenated blood, the cancer cells will die. The antiangiogenic drug bevacizumab (Avastin) has recently been found to prolong survival in advanced lung cancer when it is added to the standard chemotherapy regimen. Bevacizumab is given intravenously every two to three weeks. However, since this drug may cause bleeding, it is not appropriate for use in patients who are coughing up blood, if the lung cancer has spread to the brain, or in people who are receiving anticoagulation therapy ("blood thinner" medications). Bevacizumab is also not used in cases of squamous cell cancer, because it leads to bleeding from this type of lung cancer.
Photodynamic therapy (PDT): One newer therapy used for different types and stages of lung cancer (as well as some other cancers) is photodynamic therapy. In photodynamic treatment, a photosynthesizing agent (such as a porphyrin, a naturally occurring substance in the body) is injected into the bloodstream a few hours prior to surgery. During this time, the agent deposits itself selectively in rapidly growing cells such as cancer cells. A procedure then follows in which the physician applies a certain wavelength of light through a handheld wand directly to the site of the cancer and surrounding tissues. The energy from the light activates the photosensitizing agent, causing the production of a toxin that destroys the tumor cells. PDT has the advantages that it can precisely target the location of the cancer, is less invasive than surgery, and can be repeated at the same site if necessary. The drawbacks of PDT are that it is only useful in treating cancers that can be reached with a light source and is not suitable for treatment of extensive cancers. Research is ongoing to further determine the effectiveness of PDT in lung cancer.
Radiofrequency ablation (RFA): Radiofrequency ablation is being studied as an alternative to surgery, particularly in cases of early stage lung cancer. In this newer type of treatment, a needle is inserted through the skin into the cancer, usually under guidance by CT scanning. Radiofrequency (electrical) energy is then transmitted to the tip of the needle where it produces heat in the tissues, killing the cancerous tissue and closing small blood vessels that supply the cancer. RFA usually is not painful and has been approved by the U.S. Food and Drug Administration for the treatment of certain cancers including lung cancers. Studies have shown that this treatment can prolong survival similarly to surgery, when used to treat early stages of lung cancer, but without the risks of major surgery and the prolonged recovery time associated with major surgical procedures.
Experimental therapies: Since no therapy is currently available that is absolutely effective in treating lung cancer, patients may be offered a number of new therapies that are still in the experimental stage, meaning that doctors do not yet have enough information to decide whether these therapies should become accepted forms of treatment for lung cancer. New drugs or new combinations of drugs are tested in so-called clinical trials, which are studies that evaluate the effectiveness of new medications in comparison with those treatments already in widespread use. Experimental treatments known as immunotherapies are being studied that involve the use of vaccine-related therapies or other therapies that attempt to utilize the body's immune system to fight cancer cells.
reference:http://www.medicinenet.com/lung_cancer

How is lung cancer diagnosed?

2010-01-01T09:09:00.001-08:00

Doctors use a wide range of diagnostic procedures and tests to diagnose lung cancer. These include...

The history and physical examination may reveal the presence of symptoms or signs that are suspicious for lung cancer. In addition to asking about symptoms and risk factors for cancer development such as smoking, doctors may detect signs of breathing difficulties, airway obstruction, or infections in the lungs. Cyanosis, a bluish color of the skin and the mucous membranes due to insufficient oxygen in the blood, that suggests compromised function of the lung. Likewise, changes in the tissue of the nail beds, known as clubbing, may also indicate lung disease.
The chest X-ray is the most common first diagnostic step when any new symptoms of lung cancer are present. The chest X-ray procedure often involves a view from the back to the front of the chest as well as a view from the side. Like any X-ray procedure, chest X-rays expose the patient briefly to a minimum amount of radiation. Chest X-rays may reveal suspicious areas in the lungs but are unable to determine if these areas are cancerous. In particular, calcified nodules in the lungs or benign tumors called hamartomas may be identified on a chest X-ray and mimic lung cancer.
CT (computerized axial tomography scan, or CAT scan) scans may be performed on the chest, abdomen, and/or brain to examine for both metastatic and primary tumor. A CT scan of the chest may be ordered when X-rays are do not show an abnormality or do not yield sufficient information about the extent or location of a tumor. CT scans are X-ray procedures that combine multiple images with the aid of a computer to generate cross-sectional views of the body. The images are taken by a large donut-shaped X-ray machine at different angles around the body. One advantage of CT scans is that they are more sensitive than standard chest X-rays in the detection of lung nodules. Sometimes intravenous contrast material is given prior to the procedure to help delineate the organs and their positions. A CT scan exposes the patient to a minimal amount of radiation. The most common side effect is an adverse reaction to intravenous contrast material that may have been given prior to the procedure. There may be resulting itching, a rash, or hives that generally disappear rather quickly. Severe anaphylactic reactions (life-threatening allergic reactions with breathing difficulties) to contrast material are rare. CT scans of the abdomen may identify metastatic cancer in the liver or adrenal glands, and CT scans of the head may be ordered to reveal the presence and extent of metastatic cancer in the brain.
A technique called a low-dose helical CT scan (or spiral CT scan) is sometimes used in screening for lung cancers. This procedure requires a special type of CT scanner and has been shown to be an effective tool for the identification of small lung cancers in smokers and former smokers. However, it has not yet been proven whether the use of this technique actually saves lives or lowers the risk of death from lung cancer. The heightened sensitivity of this method is actually one of the sources of its drawbacks, since lung nodules requiring further evaluation will be seen in approximately 20% of people with this technique. Of the nodules identified by low-dose helical screening CTs, 90% are not cancerous but require up to two years of costly and often uncomfortable follow-up and testing. Trials are underway to further determine the utility of spiral CT scans in screening for lung cancer.
Magnetic resonance imaging (MRI) scans may be appropriate when precise detail about a tumor's location is required. The MRI technique uses magnetism, radio waves, and a computer to produce images of body structures. As with CT scanning, the patient is placed on a moveable bed which is inserted into the MRI scanner. There are no known side effects of MRI scanning, and there is no exposure to radiation. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. People with heart pacemakers, metal implants, artificial heart valves, and other surgically implanted structures cannot be scanned with an MRI because of the risk that the magnet may move the metal parts of these structures.
Positron emission tomography (PET) scanning is a specialized imaging technique that uses short-lived radioactive drugs to produce three-dimensional colored images of those substances in the tissues within the body. While CT scans and MRI scans look at anatomical structures, PET scans measure metabolic activity and functioning of tissue. PET scans can determine whether a tumor tissue is actively growing and can aid in determining the type of cells within a particular tumor. In PET scanning, the patient receives a short half-lived radioactive drug and receives approximately the amount of radiation exposure as two chest X-rays. The drug discharges particles known as positrons from wherever they are taken up and used in the body. As the positrons encounter electrons within the body, a reaction producing gamma rays occurs. A scanner records these gamma rays and maps the area where the radioactive drug is located. For example, combining glucose (a common energy source in the body) with a radioactive substance will show where glucose is rapidly being used, for example, in a growing tumor.
Bone scans are used to create images of bones on a computer screen or on film. Doctors may order a bone scan to determine whether a lung cancer has metastasized to the bones. In a bone scan, a small amount of radioactive material is injected into the bloodstream and collects in the bones, especially in abnormal areas such as those involved by metastatic tumors. The radioactive material is detected by a scanner, and the image of the bones is recorded on a special film for permanent viewing.
Sputum cytology: The diagnosis of lung cancer always requires confirmation of malignant cells by a pathologist, even when symptoms and X-ray studies are suspicious for lung cancer. The simplest method to establish the diagnosis is the examination of sputum under a microscope. If a tumor is centrally located and has invaded the airways, this procedure, known as a sputum cytology examination, may allow visualization of tumor cells for diagnosis. This is the most risk-free and inexpensive tissue diagnostic procedure, but its value is limited since tumor cells will not always be present in sputum even if a cancer is present. Also, noncancerous cells may occasionally undergo changes in reaction to inflammation or injury that makes them look like cancer cells.
Bronchoscopy: Examination of the airways by bronchoscopy (visualizing the airways through a thin, fiberoptic probe inserted through the nose or mouth) may reveal areas of tumor that can be sampled (biopsied) for diagnosis by a pathologist. A tumor in the central areas of the lung or arising from the larger airways is accessible to sampling using this technique. Bronchoscopy may be performed using a rigid or a flexible, fiberoptic bronchoscope and can be performed in a same-day outpatient bronchoscopy suite, an operating room, or on a hospital ward. The procedure can be uncomfortable, and it requires sedation or anesthesia. While bronchoscopy is relatively safe, it must be carried out by a lung specialist (pulmonologist or surgeon) experienced in the procedure. When a tumor is visualized and adequately sampled, an accurate cancer diagnosis usually is possible. Some patients may cough up dark-brown blood for one to two days after the procedure. More serious but rare complications include a greater amount of bleeding, decreased levels of oxygen in the blood, and heart arrhythmias as well as complications from sedative medications and anesthesia.
Needle biopsy: Fine needle aspiration (FNA) through the skin, most commonly performed with radiological imaging for guidance, may be useful in retrieving cells for diagnosis from tumor nodules in the lungs. Needle biopsies are particularly useful when the lung tumor is peripherally located in the lung and not accessible to sampling by bronchoscopy. A small amount of local anesthetic is given prior to insertion of a thin needle through the chest wall into the abnormal area in the lung. Cells are suctioned into the syringe and are examined under the microscope for tumor cells. This procedure is generally accurate when the tissue from the affected area is adequately sampled, but in some cases, adjacent or uninvolved areas of the lung may be mistakenly sampled. A small risk (3%-5%) of an air leak from the lungs (called a pneumothorax, which can easily be treated) accompanies the procedure.
Thoracentesis: Sometimes lung cancers involve the lining tissue of the lungs (pleura) and lead to an accumulation of fluid in the space between the lungs and chest wall (called a pleural effusion). Aspiration of a sample of this fluid with a thin needle (thoracentesis) may reveal the cancer cells and establish the diagnosis. As with the needle biopsy, a small risk of a pneumothorax is associated with this procedure.
Major surgical procedures: If none of the aforementioned methods yields a diagnosis, surgical methods must be employed to obtain tumor tissue for diagnosis. These can include mediastinoscopy (examining the chest cavity between the lungs through a surgically inserted probe with biopsy of tumor masses or lymph nodes that may contain metastases) or thoracotomy (surgical opening of the chest wall for removal or biopsy of a tumor). With a thoracotomy, it is rare to be able to completely remove a lung cancer, and both mediastinoscopy and thoracotomy carry the risks of major surgical procedures (complications such as bleeding, infection, and risks from anesthesia and medications). These procedures are performed in an operating room, and the patient must be hospitalized.
Blood tests: While routine blood tests alone cannot diagnose lung cancer, they may reveal biochemical or metabolic abnormalities in the body that accompany cancer. For example, elevated levels of calcium or of the enzyme alkaline phosphatase may accompany cancer that is metastatic to the bones. Likewise, elevated levels of certain enzymes normally present within liver cells, including aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT), signal liver damage, possibly through the presence of metastatic tumor.

reference:http://www.medicinenet.com/lung_cancer/page5.htm#tocf

What are the types of lung cancer?

2010-01-01T09:07:00.000-08:00

Lung cancers, also known as bronchogenic carcinomas (carcinoma is another term for cancer), are broadly classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). This classification is based upon the microscopic appearance of the tumor cells themselves. These two types of cancers grow and spread in different ways and may have different treatment options, so a distinction between these two types is important.

SCLC comprise about 20% of lung cancers and are the most aggressive and rapidly growing of all lung cancers. SCLC are strongly related to cigarette smoking, with only 1% of these tumors occurring in nonsmokers. SCLC metastasize rapidly to many sites within the body and are most often discovered after they have spread extensively. Referring to a specific cell appearance often seen when examining samples of SCLC under the microscope, these cancers are sometimes called oat cell carcinomas.

NSCLC are the most common lung cancers, accounting for about 80% of all lung cancers. NSCLC can be divided into three main types that are named based upon the type of cells found in the tumor:

* Adenocarcinomas are the most commonly seen type of NSCLC in the U.S. and comprise up to 50% of NSCLC . While adenocarcinomas are associated with smoking like other lung cancers, this type is observed as well in nonsmokers who develop lung cancer. Most adenocarcinomas arise in the outer, or peripheral, areas of the lungs. Bronchioloalveolar carcinoma is a subtype of adenocarcinoma that frequently develops at multiple sites in the lungs and spreads along the preexisting alveolar walls.

* Squamous cell carcinomas were formerly more common than adenocarcinomas; at present, they account for about 30% of NSCLC. Also known as epidermoid carcinomas, squamous cell cancers arise most frequently in the central chest area in the bronchi.

* Large cell carcinomas, sometimes referred to as undifferentiated carcinomas, are the least common type of NSCLC.

* Mixtures of different types of NSCLC are also seen.

Other types of cancers can arise in the lung; these types are much less common than NSCLC and SCLC and together comprise only 5%-10% of lung cancers:

* Bronchial carcinoids account for up to 5% of lung cancers. These tumors are generally small (3-4 cm or less) when diagnosed and occur most commonly in people under 40 years of age. Unrelated to cigarette smoking, carcinoid tumors can metastasize, and a small proportion of these tumors secrete hormone-like substances that may cause specific symptoms related to the hormone being produced. Carcinoids generally grow and spread more slowly than bronchogenic cancers, and many are detected early enough to be amenable to surgical resection.

* Cancers of supporting lung tissue such as smooth muscle, blood vessels, or cells involved in the immune response can rarely occur in the lung.

As discussed previously, metastatic cancers from other primary tumors in the body are often found in the lung. Tumors from anywhere in the body may spread to the lungs either through the bloodstream, through the lymphatic system, or directly from nearby organs. Metastatic tumors are most often multiple, scattered throughout the lung, and concentrated in the peripheral rather than central areas of the lung.

reference:http://www.medicinenet.com/lung_cancer/page3.htm#tocd

Early Symptoms of Lung Cancer

2009-08-30T21:56:00.000-07:00

Early Symptoms of Lung Cancer
Know the Early Symptoms of Lung Cancer
By Lynne Eldridge MD, About.com
Updated: July 28, 2009

About.com Health's Disease and Condition content is reviewed by the Medical Review Board
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Lung Adenocarcinoma

What are the early symptoms of lung cancer? We know that the survival rate from lung cancer is better the earlier it is caught. The 60% to 80% 5-year survival rate with stage 1 lung cancer drops to a saddening 10% with stage 4 disease, yet nearly half of people have progressed to this advanced stage at the time of diagnosis. What are the early symptoms of lung cancer that you should be on the lookout for?

Keep in mind that understanding the early symptoms of lung cancer is important for non-smokers as well as smokers. At present, 50% of people who develop lung cancer are former smokers, and 15% have never smoked.

A Cough That Doesn’t Go Away
Many people dismiss or adapt to a chronic cough, attributing it to something else. Perhaps it is allergies, a “leftover” cough following a cold, or dry air during the winter months. But a cough that lasts more than a few weeks can be a sign of something else. A chronic cough as an early symptom of lung cancer is even easier to miss if you have a condition that predisposes you to coughing, such as asthma, COPD, allergies, or gastroesophageal reflux. Coughing up blood (hemoptysis) is a common symptom of lung cancer, but can be fairly subtle and you may notice only a small amount of blood tinged phlegm when you cough. If you experience a persistent cough, check with your doctor, and ask for a second opinion if you don’t get a clear answer.
Shortness of Breath With Activity
Another common early symptom of lung cancer is shortness of breath that you only notice with activity. This can be overlooked and blamed on getting older, being out-of-shape, or perhaps due to those few extra pounds you've gained. If you notice that you are hesitant to take that hike, become winded with sexual activity, or blame the humidity for making it more difficult to breathe, make an appointment to talk to your doctor.
Pain or Aching in Your Shoulder, Back, Chest, or Arm
Lung cancers may press on nerves, resulting in pain in your shoulder, chest, back, or an arm -- even before they cause a cough or difficulty breathing. If you notice pain in one of these areas of the body that doesn’t seem to be related to an injury (or even if it is but persists), consult your physician. Up to 50% of people with lung cancer have some chest or shoulder pain at the time of diagnosis, especially pain that increases with coughing and breathing.
Repeated Infections Such as Bronchitis and Pneumonia
It’s not uncommon for someone to discover that they have lung cancer after being treated for repeated episodes of bronchitis or pneumonia. If a tumor is located near an airway, it can cause an obstruction that predisposes you to these infections. If you have had a few episodes of bronchitis or pneumonia, talk to your doctor. Repeated infections could be due to persistent smoking or a condition such as COPD, but they could also be an early symptom of lung cancer.
Any Abnormal Symptoms or a General Decline in Health
If you note any symptoms which are unusual for you, it is important to check with you doctor, especially if you have a history of smoking. Seemingly unrelated symptoms, such as knee pain, may be an early symptom of lung cancer. General symptoms, such as fatigue, decreased appetite, or even depression should prompt you to seek a physicians guidance, too.
With lung cancer now the leading cause of cancer deaths for both men and women in the United States, it is important to be aware of any early symptoms. That said, 25% of people have no symptoms at the time of diagnosis, and lung cancer is discovered incidentally when a chest x-ray or CT scan is done for an unrelated reason. CT screening for lung cancer is being evaluated, but it raises other issues that need to be considered. Hopefully, a test will be developed in the near future that will allow us to screen for lung cancer as we are now able to screen for some other cancers.

Sources:

Beckles, M. et al. Intitial Evaluation of the Patient with Lung Cancer: Symptoms, Signs, Laboratory Tests and Paraneoplastic Syndromes. Chest. 2003. 123(1 Suppl):97S-104S.

Buccheri, G. and D. Ferrigno. Lung cancer: clinical presentation and specialist referral time. European Respiratory Journal. 2004. 24(6):894-904.

National Cancer Institute. What You Need to Know About Lung Cancer. Symptoms. 07/26/07. http://www.cancer.gov/cancertopics/wyntk/lung/page6

2009-08-17T03:53:00.000-07:00

What is Lung Cancer