Cancers are diseases in which normal cells transform so that they grow and multiply without normal controls. In many types of cancer, this results in the growth of one or more large masses, or tumors, of these transformed cells.
Such transformed cells are said to have become malignant and are then called cancer cells. This can happen in almost any part of the body. When cancer starts in the cells normally found in the lungs, the disease is called lung cancer.
Lung cancer is one of the most common types of cancer and is the leading cause of death from cancer in men and in women. This is because the lungs are exposed to the external environment more than most other organs are. In many cases, cancer-causing substances (carcinogens) in the air are inhaled and cause cell damage that later becomes cancer. The most common cause of lung cancer, by far, is smoking.
The two main types of lung cancer are small-cell lung cancer and non-small-cell lung cancer. Non-small-cell lung cancer is a catchall term for all lung cancers that are the not small-cell type. They are grouped together because the treatment is often the same for all non-small-cell types. Together, non-small-cell lung cancers, or NSCLCs, make up a majority of lung cancers. Each type is named for the types of cells that were transformed to become cancer. The following are the most common types of NSCLC in the United States:
Like all cancers, lung cancer is most easily and successfully treated if it is caught early. An early-stage cancer is less likely to have grown to a large size or to have spread to other parts of the body (metastasized). Large or metastasized cancers are much more difficult to treat successfully. Lung cancer can advance in severity, and these advancement measures are termed stages. Stages range from I to IV, with stage IV as being the most severe stage (see staging of lung cancers below).
Exposures to the following agents account, at least partly, for some cases of lung cancer:
The symptoms of lung cancer are caused by the primary tumor or by metastatic disease. The primary tumor may press on, invade, or damage surrounding tissues, blood vessels, or nerves.
Metastatic lung cancer may cause similar problems in other parts of the body. As many as 10% of people with lung cancer have no symptoms. Their cancers are detected on chest X-ray films performed for other reasons.
The symptoms depend on the primary tumor's size, its location in the lung, the surrounding areas affected by the tumor, and the sites of tumor metastasis if any. Symptoms and signs related to the primary tumor may include any of the following:
Symptoms of metastatic lung tumors depend on location and size. Lung cancer most often spreads to the liver, the adrenal glands, the bones, and the brain. About 30%-40% of people with lung cancer have some symptoms or signs of metastatic disease.
Paraneoplastic syndromes are conditions that the disease causes indirectly. These are less common with NSCLC than with small-cell lung cancers, but they do occur.
Any pain in the chest, side, or back, breathing problem, or cough that persists, worsens, or produces blood warrants an immediate visit to a health-care professional, especially if you are or ever were a smoker.
The symptoms of lung cancer can be caused by many different medical conditions. Even a chest X-ray film that shows what looks like a tumor is not enough to make the diagnosis of lung cancer. The health-care provider's job is to gather all available information and to make the diagnosis. Correct and prompt diagnosis is essential so that appropriate treatment can be started as soon as possible.
The first step in the evaluation is the medical interview. The health-care provider asks the patient questions about symptoms and when they started, current or past medical problems, medications taken, family medical problems and family cancer history, work and travel history, and habits and lifestyle. This is followed by a thorough physical examination.
The remainder of the evaluation focuses on confirming the presence of lung cancer and staging the tumor. Although primary-care providers are able to conduct this evaluation, they may prefer to refer the patient to a specialist in lung diseases (pulmonologist) or cancer (oncologist).
No blood test can confirm that a patient has lung cancer. Blood tests are performed to check the patient's general health, to rule out other conditions that might cause similar symptoms, and to detect certain paraneoplastic syndromes. The usual blood tests include the following:
Respiratory (breathing) symptoms are usually evaluated with a chest X-ray film, CT scan of the chest, or both. X-ray films are limited in the amount of detail they provide, but they clearly show some tumors. CT scans shows much greater detail in a 3-D format. A CT scan is needed if the X-ray film findings are not definitive. If imaging studies show evidence of a tumor, further testing is needed.
Sputum analysis: Sputum is mucus in the lungs. Sputum is the body's natural system for removing small particles and contaminants from the airways. Many people, especially those who smoke, produce sputum when they cough. In some cases of lung cancer, tumor cells are sloughed off into the sputum and can be detected by cytologic (cell) testing of the sputum. For this test, the patient is asked to cough, and the sputum is collected and examined.
Bronchoscopy: This is the use of a device called an endoscope to view the lungs directly. An endoscope is a thin tube with a light and a tiny camera on the end. The endoscope is inserted through the mouth or nose into the bronchus (airway) and down to the lung. The camera transmits pictures of the inside of the patient's airways that can be viewed on a video screen.
Endobronchial ultrasound (EBUS): This technique that combines bronchoscopy with an ultrasound, allowing good visualization of lymph nodes and biopsy without an incision.
Fine-needle aspiration or core needle biopsy: These techniques allow sampling of abnormal tissue without the need for open surgery, using ultrasound, or CT scanning to localize the abnormal area. It is used for tumors that cannot be reached with a bronchoscope, usually because they are in the outer part of the lung. Again, this material is examined to confirm the presence of a tumor and to determine the type of tumor.
For certain NSCLC, genetic testing to look for mutations in the DNA of the tumor are recommended to determine whether targeted therapy (see below) may be effective. Current treatment practice is to recommend analysis of either the original tumor or of a metastasis in the case of late-stage disease, for epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) for all patients whose tumor is of a subtype known as adenocarcinoma. Testing for other tumor markers may be performed to help determine which specific drugs will be most effective for a given tumor. This testing is performed in the laboratory using biopsy tissue samples.
Biopsies from other sites: Material can also be obtained from other sites with abnormalities to confirm the diagnosis. These sites include enlarged lymph nodes or liver and collections of fluid around the lung (pleural effusion) or heart (pericardial effusion).
Staging is a system of classifying cancers based on the extent of the disease. In general, the lower the stage, the better the outlook for remission and survival. In NSCLC, staging is based on the size of the primary tumor, the number of cancerous lymph nodes, and the presence of any metastatic tumors. Accurate staging is essential in NSCLC because the stage of the cancer determines which treatment may offer the best results.
For people with lung cancer, the first step is to undergo a staging evaluation. The patient's medical team cannot make recommendations for the best treatment until they know the cancer's exact stage.
This evaluation includes many of the tests already described. Other tests are as follows:
The stage is determined by a combination of the following three characteristics:
NSCLC has four stages, designated I, II, III, and IV.
Traditionally, there are three major therapies used for NSCLC: surgery, chemotherapy, and radiation therapy. Targeted therapy is a new form of treatment that is specifically designed to treat defects in the cancer cells and requires testing of the tumor tissue to determine what specific abnormalities are present. Immunotherapy is also a newer method often used to treat NSCLC.
Each person with NSCLC should be offered a customized treatment regimen, which should consist of some combination of these therapies depending on disease stage and location, as well as the particular genetic abnormalities or so-called tumor biomarkers found in the individual tumor.
After the staging evaluation, a decision is made whether the tumor is operable. Operable (or resectable) tumors are those that can be removed completely or almost completely by surgery. Generally, only stage I and some stage II and III tumors can be removed by surgery. Sometimes, people with stage III or IV inoperable disease undergo surgery, but this is usually performed to remove enough of the tumor to relieve symptoms such as breathing problems or severe pain. Surgery does not cure people with stage IV or most stage III diseases.
NSCLC is only moderately sensitive to chemotherapy. Chemotherapy alone does not have the potential to cure people with NSCLC. When the goal is cure, chemotherapy is given in combination with surgery or radiation therapy. Chemotherapy alone is given only to people who cannot undergo surgery or radiation therapy or, in some cases, people whose disease has relapsed after surgery. When given in combination with surgery, the chemotherapy is usually given after surgery (adjuvant chemotherapy).
Adjuvant chemotherapy is recommended to treat cancer in stages I-III after surgery has been performed to remove the cancer. In general, chemotherapy is given in cycles. Treatment usually lasts a few days and is then followed by a recovery period of a few weeks. When side effects have subsided and blood cell counts have started to return to normal, the next cycle begins. Usually, chemotherapy is given in regimens of two or four cycles. After these cycles are over, the patient undergoes repeat CT scans and other tests to see what effect the chemotherapy has had on the tumor.
Radiation therapy may be given in combination with surgery or chemotherapy or alone. Generally, radiation therapy is given alone only for people who are not candidates for surgery. Radiation therapy may be used for different aspects of treatment, including preoperatively to reduce the size of a tumor for surgical removal, after surgery to kill any remaining tumor cells, or in later-stage disease to relieve the patient's symptoms.
Targeted therapy involves testing a patient's tumor tissue to identify specific genetic alterations or mutations that can be targeted with specifically designed drugs. Targeted therapy may be given alone or in combination with chemotherapy. Many NSCLC has genetic changes that include mutations or other changes in specific genes; examples of the genetic changes are EGFR mutation, ALK fusion oncogene, and mutations in genes known as ROS1, BRAF, and KRAS. A small number of NSCLC have mutations in the gene that codes for the HER2 protein. Targeted therapy drugs that attack cells with these specific changes are constantly being developed, and many of these drugs are available today.
Immunotherapy is a type of therapy that helps your immune system work to destroy tumor cells. Specific testing, known as biomarker testing, is sometimes required to determine if your particular tumor will respond to certain immunotherapy drugs.
Inoperable NSCLC is treated with chemotherapy or a combination of chemotherapy and radiation therapy. Chemotherapy usually requires other supportive medications to prevent or treat side effects such as:
Because neutropenia increases the risk of infections, antibiotics may also be given. Growth factors are often given to promote the production of red and white blood cells and platelets. The agents most widely used to prevent or treat nausea and vomiting are:
Examples of chemotherapy agents that are currently used to treat NSCLC include the following:
Examples of targeted therapy agents that are currently used to treat NSCLC include the following:
Examples of immunotherapy agents that are currently used to treat NSCLC include the following:
Clinical trials should always be considered as an alternative in the treatment of advanced non-small-cell lung cancer. Clinical trials are always under way to test new medications, including new targeted therapy and immunotherapy drugs, as well as new combinations of drugs.
Following surgery for any operable lung cancer, the patient has a risk of developing a second primary lung cancer. Following any treatment, the original tumor may come back.
Palliative care refers to medical or nursing care whose goal is to reduce symptoms and suffering without attempting to cure the underlying disease. Because only a small number of people with lung cancer are cured, relief of suffering becomes the primary goal for many. Palliative care consultation can prolong survival in patients with advanced inoperable lung cancer.
Palliative care may be undertaken through the provider's office, and care may be given at home. Palliative care consists of both counseling and coordination of care to be sure that the patients understand the goals of treatment and participates in their treatment decisions at each step. It also helps to manage symptoms optimally and coordinates care of preexistent conditions in the face of the cancer diagnosis.
Palliative care is not the same as hospice care.
End-of-life care with the aid of hospice providers usually comes at the point when palliative measures, including active treatments with chemotherapy and radiation, are generally recognized as no longer effective even in palliating the disease or halting its progression. At that point, an early referral to hospice is appropriate. Hospice providers can coordinate and manage symptoms at home in a special hospice facility, or when necessary, a nursing home or hospital.
Lung cancer remains a highly preventable disease because 85% of lung cancers occur in people who smoke or used to smoke. The best way to prevent lung cancer is not to smoke.
Overall, 14% of people with NSCLC survive for at least five years.
How well the person with NSCLC functions can have a strong effect on the survival duration. A person with small-cell lung cancer who functions well has an advantage over someone who cannot work or pursue normal activities.
Living with cancer presents many new challenges, both for you and for your family and friends.
For most people with cancer, talking about their feelings and concerns helps.
For more information about support groups, contact the following agencies:
National Cancer Institute, General Information About Non-Small Cell Lung Cancer
It's Time to Focus on Lung Cancer, Lung Cancer 101
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.
