What Is Small-Cell Lung Cancer (SCLC)?
When cells of the lung start to undergo a degenerative transformation in appearance and start growing rapidly in an uncontrolled manner, the condition is called lung cancer. Lung cancer can affect any part of the lung. Lung cancer is the leading cause of cancer deaths in both women and men in the United States, Canada, and China. Two main types of lung cancer exist: small-cell lung cancer (SCLC, or small cell lung carcinoma, also formerly called oat cell cancer) and non-small-cell lung cancer (NSCLC). Most lung cancers are NSCLC, including squamous cell carcinoma and adenocarcinoma of the lung. Small-cell lung cancer accounts for only approximately 15% of all cases of lung cancer. Small-cell lung cancer differs from non-small-cell lung cancer in the following ways:
- Small-cell lung cancer grows rapidly. The time from the development of symptoms to diagnosis is usually 90 days or less.
- Small-cell lung cancer spreads quickly. From 67%-75% of people who develop small cell lung cancer will have spread of the cancer outside of the lung to other parts of the body at the time of initial diagnosis.
- Small-cell lung cancer responds well to chemotherapy (using medications to kill cancer cells) and radiation therapy (using high-dose X-rays or other high-energy rays to kill cancer cells).
- SCLC is frequently associated with distinct paraneoplastic syndromes (collection of symptoms that may result from substances produced by the tumor, the effects of which may occur systematically or at other areas separate from those with direct cancer involvement).
What Are Causes and Risk Factors of Small-Cell Lung Cancer?
- The predominant cause of both small-cell lung cancer and non-small-cell lung cancer is tobacco smoking. However, small-cell lung cancer is more strongly linked to smoking than non-small-cell lung cancer.
- Even secondhand tobacco smoke is a risk factor for lung cancer.
- All types of lung cancers occur with increased frequency in people who mine uranium, but small-cell lung cancer is most common. The prevalence is increased further in people who smoke.
- Exposure to radon (an inert gas that develops from the decay of uranium) has been reported to cause small-cell lung cancer.
- Exposure to asbestos increases the risk of lung cancer by nine times. A combination of asbestos exposure and cigarette smoking increases the risk by as much as 50 times.
What Are Small-Cell Lung Cancer Symptoms and Signs?
People with small-cell lung cancer typically have had symptoms for a relatively short time (eight to 12 weeks) before they visit their doctor.
The symptoms can result from local growth of the tumor, spread to nearby areas, distant spread, paraneoplastic syndromes, or a combination thereof.
Symptoms and signs due to local growth of the tumor include the following:
Symptoms and signs due to spread of the cancer to nearby areas include the following:
- Hoarseness of voice, resulting from compression of the nerve that supplies the vocal cords
- Shortness of breath, resulting from compression of the nerve that supplies the muscles of the diaphragm or severe shortness of breath, and stridor (sound produced by turbulent flow of air through a narrowed part of the respiratory tract), resulting from compression of the trachea (windpipe) and larger bronchi (airways of the lung)
- Difficulty swallowing, resulting from compression of the esophagus (food pipe)
- Swelling of the face and hands, resulting from compression of the superior vena cava (vein that returns deoxygenated blood from the upper body)
Symptoms and signs due to distant cancer spread depend on the site of spread and include the following:
- Spread to the brain can cause headache, blurring of vision, nausea, vomiting, and weakness of any limb.
- Spread to the vertebral column can cause central back pain.
- Spread to the spinal cord can cause paralysis.
- Spread to the bone can cause bone pain.
- Spread to the liver can cause pain in the right upper part of the abdomen.
Symptoms and signs due to paraneoplastic syndromes include the following:
- Symptoms may or may not be characteristic of a specific organ system.
- Nonspecific symptoms include fatigue, loss of appetite, and weight loss.
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a paraneoplastic syndrome that can occur with small-cell lung cancer or other cancers. It is characterized by excessive levels of antidiuretic hormone that lead to low blood sodium levels and nerve and muscular problems.
Small-Cell Lung Cancer Symptom
If a cough is a warning sign of an underlying cancer, the person may have a group of symptoms. If lung cancer or a cancer of the air passages is present, the person may cough up blood. Other signs and symptoms that may warn of a cancer include worsening fatigue, loss of appetite, unexplained loss of weight, or decreased ability to swallow solid or liquid foods.
When to Seek Medical Care
Consult a doctor if any of the following symptoms and signs are present:
- Shortness of breath
- Chest pain
- Coughing up blood
- Unexplained weight loss
- Unexplained persistent fatigue
- Unexplained deep aches or pains
Go immediately to the nearest hospital emergency department if any of the following symptoms or signs are present:
- Coughing up large amounts of blood
- Chest pain that does not go away
- Sudden shortness of breath
- Sudden weakness of any limb
- Sudden vision problems
What Exams and Tests Help Diagnose Small-Cell Lung Cancer?
Initial examinations and tests for suspected lung cancer can include the following:
- Your health care provider will ask you questions about your medical, surgical, work, and smoking history.
- Physical examination to check for general signs of health
- Chest X-ray film
- Sputum cytology: Cells in the sputum are examined to see if they are cancerous.
- CT scan of the chest: An X-ray machine linked to a computer takes a series of detailed pictures of the inside of the chest from different angles. Other names of this procedure are computed tomography, computerized tomography, or computerized axial tomography.
- Thoracentesis: The lungs are enclosed in a sac. Lung cancer can cause fluid to collect in this sac. This is called pleural effusion. In people who have cancer, this fluid may contain cancer cells. The fluid is removed by a needle and examined for the presence of cancer cells. This fluid is usually visible on chest X-ray.
- Bronchoscopy: This is a procedure used to look inside the trachea (windpipe) and large airways in the lung for abnormal areas. A bronchoscope (a thin, flexible, lighted tube with a tiny camera on the end) is inserted through the mouth or nose and down the windpipe. From there, it can be inserted into the airways (bronchi) of the lungs. During bronchoscopy, the doctor looks for tumors and takes a biopsy sample (a sample of cells that is removed for examination under a microscope) from the airways.
- Lung biopsy: If a tumor is on the periphery of the lung, it may not be seen with bronchoscopy. Instead, a biopsy sample has to be taken with the help of a needle inserted through the chest wall and into the tumor. This procedure is called transthoracic needle aspiration biopsy. Most small cell lung cancer arises centrally in the chest.
- Mediastinoscopy: This procedure is performed to determine the extent the tumor has spread into the mediastinum (area of the chest between the lungs). Mediastinoscopy is a procedure in which a tube is inserted behind the breastbone through a small cut at the lowest part of the neck. Samples of the lymph nodes (small, bean-shaped structures found throughout the body) are taken from this area to look for cancer cells.
Once the patient has been diagnosed with lung cancer, examinations and tests are performed to find out whether the cancer has spread (metastasized) to other organs of the person's body. These examinations and tests help to determine the stage of the cancer. Staging is important because lung cancer treatment is based on the stage of the cancer. Examinations and tests used to detect the spread of cancer may include the following:
- Blood tests: Complete blood count (CBC) (provides information about the type and count of different types of blood cells), serum electrolytes, renal function studies (for assessing kidney function), and liver function tests are all part of the routine tests for staging. In some cases, these tests may identify the site of metastasis. For instance, an elevated serum calcium level is seen with spread of the cancer to the bone. These tests are also important to assess the organ functions before starting treatment.
- CT scan of the brain, neck, abdomen, and pelvis to identify possible spread of the cancer
- MRI of the brain and spine: MRI is an imaging technique used to produce high-quality images of the inside of the body. A series of detailed pictures of areas inside the body are taken from different angles. The difference between an MRI and CT scan is that MRI uses magnetic waves, whereas CT scan uses X-rays for the procedure. Depending on the area to be studied and what the concerns are, one test might be better than the other.
- Radionuclide bone scan: With the help of this procedure, the doctor determines whether the lung cancer has spread to the bones. The doctor injects a minute quantity of radioactive material into the vein; this material travels through the bloodstream. If the cancer has spread to the bones, the radioactive material collects in the bones and is detected by a scanner.
- PET scans are used only to differentiate limited disease confined to a single radiation field from extensive metastatic disease at the time of initial diagnosis. Otherwise PET scans are not used in the management of small-cell lung cancer.
Staging of small-cell lung cancer
Staging of the cancer provides important information about the outlook of the patient's condition and helps the doctor plan the best treatment. Although other cancers are staged from stage I to stage IV, small-cell lung cancer is classified into two stages.
- Limited stage: In this stage, the tumor is confined to a single radiation field. This includes the lung and the lymph nodes, within and between the lungs.
- Extensive stage: In this stage, cancer has spread from the lung to other organs of the body. This includes the presence of fluid in the lining of the lung (pleural effusion).
What Are Small-Cell Lung Cancer Treatment Options?
The most effective treatment for small-cell lung cancer is chemotherapy (using medications to kill cancer cells), either alone or in combination with radiation therapy (using high-dose X-rays or other high-energy rays to kill cancer cells).
What Medications Treat Small-Cell Lung Cancer?
Chemotherapy uses powerful medications to kill cancer cells. These medications may be taken by mouth (orally), but they are usually injected into a vein (IV).
Chemotherapy is a systemic treatment because the medications enter the bloodstream, travel throughout the body, and kill cancer cells wherever they are. However, some normal cells are also killed. This is responsible for some of the side effects of chemotherapy.
Chemotherapy is usually given at intervals to ensure that the bone marrow has recovered before the next dose of chemotherapy is given.
Extensive research and clinical trials have identified different chemotherapy medications in the last three decades for the treatment of lung cancer. Response rates with these medications have been found to be more than 80% in patients with small-cell lung cancer who were previously untreated.
Some medications are used alone, while some are used in combination with others for greater effectiveness. An oncologist (cancer specialist) recommends chemotherapy specific to the patient's condition.
Chemotherapy medications used for the treatment of small-cell lung cancer include the following:
- Etoposide (Toposar, VePesid) is an effective antitumor medication. It slows or stops the growth of cancer cells in the body by causing breakage in the DNA (genetic material) strand. It may be given as an IV injection or as a pill.
- Cyclophosphamide (Cytoxan, Neosar) interferes with the growth of normal cells and cancer cells. It slows the growth of cancer cells and their spread in the body. It may be given as an IV injection or as a pill.
- Doxorubicin (Adriamycin, Rubex) causes destruction of DNA, which slows or stops the growth and spread of cancer cells in the body. It is an IV medication.
- Vincristine (Oncovin) is a plant-based compound. It causes cell death by interfering with the way genetic material (DNA) multiplies in the cell. It is only available as an IV medication.
- Topotecan (Hycamtin) interferes with the growth of cancer cells by inhibiting the duplication of DNA. It is an IV medication.
- Paclitaxel (Taxol) interferes with the growth of cancer cells and slows their growth and spread in the body. It is an IV medication.
- Cisplatin (Platinol) causes breakage in the DNA (genetic material) strand and interferes with cell growth. It is an IV medication.
- Carboplatin (Paraplatin) is similar to cisplatin. It also causes breakage in the DNA (genetic material) strand and interferes with cell growth. Its effectiveness is similar to cisplatin, but it is better tolerated and has lesser side effects.
- Irinotecan (Camptosar) acts in a similar manner as topotecan to decrease cancer cell growth by causing damage to cancer cell DNA. It is an IV medication.
See Understanding Lung Cancer Medications for more information.
Commonly used chemotherapy regimens in small-cell lung cancer include the following:
- CAV (cyclophosphamide, doxorubicin [Adriamycin], and vincristine): This is the old standard of care therapy for small cell lung cancer.
- PE (cisplatin or carboplatin and etoposide): This is the standard of care therapy in the United States.
- CAVE (cyclophosphamide, doxorubicin [Adriamycin], vincristine, and etoposide)
- PEC (paclitaxel, etoposide, and carboplatin)
- Topotecan alone, used for people who have progressed on the initial therapy for small cell lung cancer
- Etoposide alone, used orally primarily for elderly or infirm people
- Cisplatin and irinotecan: This is the standard of care therapy in Japan
Treatment of limited-stage small-cell lung cancer
- Currently, cisplatin, etoposide, vincristine, doxorubicin, and cyclophosphamide are the most commonly used medications for the treatment of people with small-cell lung cancer.
- Standard treatment of small-cell lung cancer involves combination chemotherapy with a cisplatin-containing regimen. Treatment cycles are repeated every three weeks. People generally receive treatment for four to six cycles.
- The combination of cisplatin and etoposide (PE) is the most widely used regimen in both limited- and extensive-stage small-cell lung cancer.
- More recently, paclitaxel and topotecan have emerged as effective medications in people with small-cell lung cancer who have not been previously treated. The response rates range from approximately 40% with topotecan to 50% with paclitaxel.
- Some doctors start radiotherapy to the chest as early as possible, while others may give it with the fourth cycle of chemotherapy.
- Radiation and chemotherapy: Sequential-radiation treatment may be given, followed by chemotherapy.
- If the patient is completely freed of the cancer, radiation therapy may be given to the patient's skull to reduce the risk of small-cell lung cancer spreading to his or her brain. This is called prophylactic cranial irradiation (PCI). It is usually given after the patient has completed the full chemotherapy and radiotherapy (to the thorax) regimen.
Treatment of extensive-stage small-cell lung cancer (small-cell lung cancer that remains incurable with current treatment options)
- People with extensive-stage small-cell lung cancer are treated with combination chemotherapy. Currently, the combination of cisplatin or carboplatin and etoposide (PE) is the most widely used regimen.
- Radiation therapy may be used for relief of the following symptoms:
- Bone pain
- Compression of the food pipe (esophagus), windpipe, or superior vena cava caused by tumors
- If the person has a complete response or their extensive disease to chemotherapy, radiation may be offered to the chest to consolidate the response and to the brain to prevent metastasis in not present (prophylactic cranial irradiation).
Treatment of relapse of small-cell lung cancer
- People who have a relapse of small-cell lung cancer have an extremely poor prognosis.
- If the disease does not respond to treatment or progresses on initial treatment (for example, refractory disease) or if the disease relapses within six months of completion of therapy, the person has little chance of responding to additional chemotherapy.
- People whose cancer does not progress for more than six months may be given additional chemotherapy. These people may even be treated with the same chemotherapy regimen which resulted in the first remission.
The immunotherapy drugs nivolumab (Opdivo) alone and in combination with ipilimumab (Yervoy), commonly used in treating advanced non-small-cell lung cancer, have been studied and have shown some effectiveness in patients with recurrent advanced small-cell lung cancer who have already received chemotherapy. More research is needed to determine the value of this kind of therapy in people with small-cell lung cancer.
- People with relapsed or refractory small-cell lung cancer may enroll in clinical trials. For information about ongoing clinical trials, visit the National Cancer Institute's Clinical Trials.
Other drugs may also be given to prevent and treat adverse effects of radiation or chemotherapy, such as nausea or vomiting. Pain medications are also important to relieve pain due to cancer or surgery.
Does Surgery Treat Small-Cell Lung Cancer?
Surgery plays little, if any, role in the management of small-cell lung cancer because almost all cancers have spread by the time they are discovered.
The exceptions are the relatively small number of people (<5%) whose cancer is discovered at a very early stage of the disease, when the cancer is confined to the lung without any spread to the lymph nodes. Patients who are diagnosed with small-cell lung cancer at a very early stage of the disease may undergo surgical removal of the lung tumor as the initial diagnostic procedure. However, surgery alone is not considered curative, so chemotherapy, usually with radiation is also administered.
Follow-Up After Treatment of Small-Cell Lung Cancer
- Patients who are receiving chemotherapy require close monitoring for side effects and their response to therapy.
- A blood workup, including CBC (complete blood count), is needed prior to each cycle of chemotherapy to ensure that the bone marrow has recovered before the next dose of chemotherapy is given.
- Kidney function should be monitored, especially if the patient is taking cisplatin, as it can damage the kidneys.
- Hearing may need to be monitored for patients receiving cisplatin.
- Electrolytes need to be managed for patients on cisplatin, as cisplatin and carboplatin can cause a drop in serum magnesium, which can result in serious cardiac rhythm problems.
- The patient may be advised to undergo a CT scan after two cycles of therapy to assess response to the therapy.
Palliative and terminal care
Because small-cell lung cancer is most frequently diagnosed in many people when it is not curable, palliative care becomes important. The goal of palliative and terminal care is to enhance the person's quality of life.
The patient may be given radiation therapy as palliative treatment to relieve symptoms caused by compression of the food pipe, windpipe, or superior vena cava.
Palliative care offers the patient emotional and physical comfort and relief from pain. Palliative care not only focuses on comfort but also addresses the concerns of the patient's family and loved ones. The patient's caregivers may include family and friends in addition to doctors and other health care professionals.
Palliative and terminal care is often given in a hospital, hospice, or nursing home; however, it can also be provided at home.
Other risk factors for lung cancer include asbestos, radon, and uranium exposure. Take precautions to reduce or eliminate exposure to such harmful substances.
Smoking cessation is associated with fewer respiratory infections and better lung function especially in limited stage small cell lung cancer. Smoking cessation can be aided with the use of nicotine gum, medicated nicotine sprays or inhalers, nicotine patches, and oral medications including Chantix and bupropion. In addition, group therapy and behavioral training further increase the chances of quitting.
What Is the Prognosis of Small-Cell Lung Cancer?
The success of treatment depends on the stage of small-cell lung cancer.
The five-year survival rate for patients with stage I SCLC is 31%.
In approximately 65%-70% of people with small-cell lung cancer, the disease has already spread to other organs of the body by the time small-cell lung cancer is diagnosed.
The stage II SCLC survival rate is about 19%.
People with small-cell lung cancer in the advanced stage cannot be cured. They usually survive less than one year.
Treatment may be moderately successful for people with limited-stage disease. However, even with limited-stage disease, the median survival time is less than two years.
The overall five-year survival rate for people with small-cell lung cancer is less than 20%. People with small cell lung cancer have the highest rate of developing a second primary cancer, usually in 5%-10% percent of cases but as high as 30%
Is It Possible to Prevent Small-Cell Lung Cancer?
Small-cell lung cancer is strongly associated with tobacco smoking. Smoking cessation and avoidance as well as avoidance of secondhand smoke can help lower your risk of developing lung cancer. Minimizing exposure to radon and asbestos will also reduce the risk.
Support Groups and Counseling for Small-Cell Lung Cancer
Support groups and counseling can help you feel less alone and can improve your ability to deal with the uncertainties and challenges that cancer brings.
Cancer support groups provide a forum where patients with cancer, survivors of cancer, or both can discuss the challenges that accompany the illness and guide you to deal with your concerns.
Support groups provide an opportunity to exchange information about the disease, take advice about managing side effects, and share your feelings with others who are undergoing a similar situation.
Support groups also help your family and friends deal with the stress.
Many organizations offer support groups for people with cancer and their family members or friends of people who have cancer. You can get information about such groups from your doctor, nurse, or hospital social worker.
The following organizations can help you with support and counseling:
- The AMC Cancer Information and Counseling Line provides current medical information and counseling for cancer issues.
- The Lung Cancer Alliance operates a national "phone buddies" program, in addition to other services.
- The National Coalition for Cancer Survivorship is a survivor-led advocacy organization working exclusively on behalf of people with all types of cancer and their families.
For More Information on Small-Cell Lung Cancer
American Cancer Society
American Lung Association
61 Broadway, 6th Floor
New York, NY 10006
National Cancer Institute, Cancer Information Service
NCI Public Inquiries Office
6116 Executive Blvd
Bethesda, MD 20892-8322
American Society of Clinical Oncology
1900 Duke Street, Suite 200
Alexandria, VA 22314
National Cancer Institute, Small Cell Lung Cancer: Treatment
American Medical Association, Atlas of the Body: The Respiratory System -- Basic Function
Lung Cancer Online
National Institutes of Health, National Cancer Institute
Pictures of Small-Cell Lung Cancer
Chest X-ray film that shows a shadow in the left lung, which was later diagnosed as lung cancer
CT scan of the lung that shows a mass lesion in the right lung, which was diagnosed as lung cancer based on needle biopsy.
Reviewed on 9/11/2017
"Pathobiology and staging of small cell carcinoma of the lung"
United States. National Cancer Institute. "Small Cell Lung Cancer Treatment." Jan. 20, 2017. <https://www.cancer.gov/types/lung/hp/small-cell-lung-treatment-pdq>.