Small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung.
Anatomy of the respiratory system, showing the trachea and both lungs and their lobes and airways. Lymph nodes and the diaphragm are also shown. Oxygen is inhaled into the lungs and passes through the thin membranes of the alveoli and into the bloodstream (see inset).
The lungs are a pair of cone-shaped breathing organs that are found in the chest. The lungs bring oxygen into the body when you breathe in and take out carbon dioxide when you breathe out. Each lung has sections called lobes. The left lung has two lobes. The right lung, which is slightly larger, has three. A thin membrane called the pleura surrounds the lungs. Two tubes called bronchi lead from the trachea (windpipe) to the right and left lungs. The bronchi are sometimes also affected by lung cancer. Small tubes called bronchioles and tiny air sacs called alveoli make up the inside of the lungs.
There are two main types of small cell lung cancer.
These two types include many different types of cells. The cancer cells of each type grow and spread in different ways. The types of small cell lung cancer are named for the kinds of cells found in the cancer and how the cells look when viewed under a microscope:
Small cell carcinoma (oat cell cancer).
Combined small cell carcinoma.
Smoking is the major risk factor for small cell lung cancer.
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for lung cancer.
Risk factors for lung cancer include the following:
Smoking cigarettes, pipes, or cigars is the most common cause of lung cancer. The earlier in life a person starts smoking, the more often a person smokes, and the more years a person smokes, the greater the risk of lung cancer. If a person has stopped smoking, the risk becomes lower as the years pass.
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk to your doctor if you think you may be at risk.
Risk factors for small cell lung cancer include:
Smoking cigarettes, pipes, or cigars, now or in the past. This is the most important risk factor for lung cancer. The earlier in life a person starts smoking, the more often a person smokes, and the more years a person smokes, the greater the risk of lung cancer.
Being exposed to secondhand smoke.
Being exposed to radiation from any of the following:
Radiation therapy to the breast or chest.
Radon in the home or workplace.
Imaging tests such as CT scans.
Atomic bomb radiation.
Living where there is air pollution.
Having a family history of lung cancer.
Being infected with the human immunodeficiency virus (HIV).
Taking beta carotene supplements and being a heavy smoker.
Older age is the main risk factor for most cancers. The chance of getting cancer increases as you get older.
When smoking is combined with other risk factors, the risk of lung cancer is increased.
Signs and symptoms of small cell lung cancer:
Coughing
Shortness of breath
Chest pain
These and other signs and symptoms may be caused by small cell lung cancer or by other conditions. Check with your doctor if you have any of the following:
Chest discomfort or pain.
A cough that doesn’t go away or gets worse over time.
Trouble breathing.
Wheezing.
Blood in sputum (mucus coughed up from the lungs).
Tests and procedures that examine the lungs are used to detect (find), diagnose, and stage small cell lung cancer.
The following tests and procedures may be used:
Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits, including smoking, and past jobs, illnesses, and treatments will also be taken.
Laboratory tests: Medical procedures that test samples of tissue, blood, urine, or other substances in the body. These tests help to diagnose disease, plan and check treatment, or monitor the disease over time.
X-ray of the chest. X-rays are used to take pictures of organs and bones of the chest. X-rays pass through the patient onto film.
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
CT scan (CAT scan) of the brain, chest, and abdomen: A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
Sputum cytology: A microscope is used to check for cancer cells in the sputum (mucus coughed up from the lungs).
Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The different ways a biopsy can be done include the following:
Fine-needle aspiration biopsy of the lung. The patient lies on a table that slides through the computed tomography (CT) machine, which takes x-ray pictures of the inside of the body. The x-ray pictures help the doctor see where the abnormal tissue is in the lung. A biopsy needle is inserted through the chest wall and into the area of abnormal lung tissue. A small piece of tissue is removed through the needle and checked under the microscope for signs of cancer.
Fine-needle aspiration (FNA) biopsy of the lung: The removal of tissue or fluid from the lung, using a thin needle. A CT scan, ultrasound, or other imaging procedure is used to find the abnormal tissue or fluid in the lung. A small incision may be made in the skin where the biopsy needle is inserted into the abnormal tissue or fluid. A sample is removed with the needle and sent to the laboratory. A pathologist then views the sample under a microscope to look for cancer cells. A chest x-ray is done after the procedure to make sure no air is leaking from the lung into the chest.
Bronchoscopy. A bronchoscope is inserted through the mouth, trachea, and major bronchi into the lung, to look for abnormal areas. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a cutting tool. Tissue samples may be taken to be checked under a microscope for signs of disease.
Bronchoscopy: A procedure to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope is inserted through the nose or mouth into the trachea and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.
Thoracoscopy: A surgical procedure to look at the organs inside the chest to check for abnormal areas. An incision (cut) is made between two ribs, and a thoracoscope is inserted into the chest. A thoracoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue or lymph node samples, which are checked under a microscope for signs of cancer. In some cases, this procedure is used to remove part of the esophagus or lung. If certain tissues, organs, or lymph nodes can’t be reached, a thoracotomy may be done. In this procedure, a larger incision is made between the ribs and the chest is opened.
Thoracentesis: The removal of fluid from the space between the lining of the chest and the lung, using a needle. A pathologist views the fluid under a microscope to look for cancer cells.
Mediastinoscopy: A surgical procedure to look at the organs, tissues, and lymph nodes between the lungs for abnormal areas. An incision (cut) is made at the top of the breastbone and a mediastinoscope is inserted into the chest. A mediastinoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue or lymph node samples, which are checked under a microscope for signs of cancer.
Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
Immunohistochemistry: A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
The stage of the cancer (whether it is in the chest cavity only or has spread to other places in the body).
The patient’s age, gender, and general health.
For certain patients, prognosis also depends on whether the patient is treated with both chemotherapy and radiation.
For most patients with small cell lung cancer, current treatments do not cure the cancer.
If lung cancer is found, patients should think about taking part in one of the many clinical trials being done to improve treatment. Clinical trials are taking place in most parts of the country for patients with all stages of small cell lung cancer. Information about ongoing clinical trials is available from the NCI Web site. You can also see lung cancer clinical trials at Fox Chase.
Stages of Small Cell Lung Cancer
After small cell lung cancer has been diagnosed, tests are done to find out if cancer cells have spread within the chest or to other parts of the body.
The process used to find out if cancer has spread within the chest or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. Some of the tests used to diagnose small cell lung cancer are also used to stage the disease. (See the General Information section.)
Other tests and procedures that may be used in the staging process include the following:
MRI (magnetic resonance imaging) of the brain: A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the brain, chest or upper abdomen, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do. A PET scan and CT scan may be done at the same time. This is called a PET-CT.
Bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
There are three ways that cancer spreads in the body.
Cancer can spread through tissue, the lymph system, and the blood:
Tissue. The cancer spreads from where it began by growing into nearby areas.
Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.
Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if small cell lung cancer spreads to the brain, the cancer cells in the brain are actually lung cancer cells. The disease is metastatic small cell lung cancer, not brain cancer.
The following stages are used for small cell lung cancer:
Limited-Stage Small Cell Lung Cancer
In limited-stage, cancer is in the lung where it started and may have spread to the area between the lungs or to the lymph nodes above the collarbone.
Extensive-Stage Small Cell Lung Cancer
In extensive-stage, cancer has spread beyond the lung or the area between the lungs or the lymph nodes above the collarbone to other places in the body.
Recurrent Small Cell Lung Cancer
Recurrent small cell lung cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the chest, central nervous system, or in other parts of the body.
Treatment Option Overview
There are different types of treatment for patients with small cell lung cancer.
Different types of treatment are available for patients with small cell lung cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Five types of standard treatment are used:
Surgery
Surgery may be used if the cancer is found in one lung and in nearby lymph nodes only. Because this type of lung cancer is usually found in both lungs, surgery alone is not often used. During surgery, the doctor will also remove lymph nodes to find out if they have cancer in them. Sometimes, surgery may be used to remove a sample of lung tissue to find out the exact type of lung cancer.
Even if the doctor removes all the cancer that can be seen at the time of the operation, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. Prophylactic cranial irradiation (radiation therapy to the brain to reduce the risk that cancer will spread to the brain) may also be given. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Laser therapy
Laser therapy is a cancer treatment that uses a laser beam (a narrow beam of intense light) to kill cancer cells.
Endoscopic stent placement
An endoscope is a thin, tube-like instrument used to look at tissues inside the body. An endoscope has a light and a lens for viewing and may be used to place a stent in a body structure to keep the structure open. An endoscopic stent can be used to open an airway blocked by abnormal tissue.
New types of treatment are being tested in clinical trials.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.
Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.
Treatment Options by Stage
Limited-Stage Small Cell Lung Cancer
Treatment of limited-stage small cell lung cancer may include the following:
Combination chemotherapy and radiation therapy to the chest. Radiation therapy to the brain may later be given to patients with complete responses.
Combination chemotherapy alone for patients who cannot be given radiation therapy.
Surgery followed by chemotherapy.
Surgery followed by chemotherapy and radiation therapy.
Radiation therapy to the brain may be given to patients who have had a complete response, to prevent the spread of cancer to the brain.
Clinical trials of new chemotherapy, surgery, and radiation treatments.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with limited stage small cell lung cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
Extensive-Stage Small Cell Lung Cancer
Treatment of extensive-stage small cell lung cancer may include the following:
Combination chemotherapy.
Radiation therapy to the brain, spine, bone, or other parts of the body where the cancer has spread, as palliative therapy to relieve symptoms and improve quality of life.
Radiation therapy to the chest may be given to patients who respond to chemotherapy.
Radiation therapy to the brain may be given to patients who have had a complete response, to prevent the spread of cancer to the brain.
Clinical trials of new chemotherapy treatments.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with extensive stage small cell lung cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
Treatment Options for Recurrent Small Cell Lung Cancer
Treatment of recurrent small cell lung cancer may include the following:
Chemotherapy.
Radiation therapy as palliative therapy to relieve symptoms and improve quality of life.
Laser therapy, stent placement to keep airways open, and/or internal radiation therapy as palliative therapy to relieve symptoms and improve quality of life.
Clinical trials of new chemotherapy treatments.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with recurrent small cell lung cancer. You can also see lung cancer clinical trials at Fox Chase. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
To Learn More About Small Cell Lung Cancer
For more information from the National Cancer Institute about small cell lung cancer, see the following:
