Carolyn Vachani, MSN, RN, AOCN and Charles B. Simone II, MD
Updated by: Christina Bach, MBE, MSW, LCSW, OSW-C
Last Modified: January 19, 2016
The lungs are two spongy organs found in the chest. They are responsible for delivering oxygen to the bloodstream. When you take a breath in, air moves into the lungs causing them to expand. The air can then come very close to blood that is traveling in small vessels called capillaries. When you breathe out, you exhale substances that you don't need, like carbon dioxide. The lungs are specially designed to place blood in close contact with as much air as possible, so their tissues are very delicate. The right lung has three sections, which are called lobes; the left lung has two lobes. Air comes in through your mouth and nose and then travels down a tube, called the trachea, to the lungs. The trachea divides into smaller branches called bronchi, and the bronchi keep dividing and dividing like branches on a tree. As the branches get smaller, they are called bronchioles. At the end of the branches, there are little sacs of air called alveoli. The air comes into contact with blood in the alveoli. The lungs are exposed to whatever you breathe in, so any toxic chemicals or pollutants in the air you breathe can get into your body through your lungs.
Lung cancer occurs when cells in the lung begin to grow out of control and can then invade nearby tissues or spread throughout the body. Large collections of cancer cells are called tumors. Cells in any of the tissues in the lung can develop cancer; but most commonly, lung cancer comes from the lining of the bronchi. Lung cancer is not really thought of as a single disease, but rather a collection of several diseases that are characterized by the cell type that makes them up, how they behave, and how they are treated. Lung cancer is divided into two main categories:
Lung cancer is the most common cause of cancer death worldwide for both men and women, with an estimated 1.6 million new cases and 1.4 million deaths annually. In the United States alone, it is estimated that 228,190 people were diagnosed and 158,040 people died from lung cancer in 2013. In comparison, 117,000 people were expected to die from colon, breast and prostate cancer combined in 2015 (the 1st, 3rd, and 4th most common cancers in the U.S.). However, the rate of diagnosis for new lung cancer cases has been falling on average 1.7% each year, over the last 10 years. Death rates have fallen on average 2.0% each year from 2003-2012.
While there are a few potential causes of lung cancer, by far the most common is smoking tobacco. Every smoker (current or former) is at risk for lung cancer. It is estimated that 80-90% of all cases of lung cancer are caused by cigarette smoking, with small cell lung cancer occurring almost exclusively in people with a smoking history. Your risk of getting lung cancer from cigarette smoking increases the longer you smoke, the more you smoke, and the deeper you inhale. Smoking low tar cigarettes does not prevent you from getting lung cancer. Importantly, if you quit smoking, your risk of getting lung cancer declines. The longer you go without smoking, the greater your risk declines. It is never too late to quit because your risk declines no matter how long you have been smoking.
What if you have already been diagnosed with a lung cancer? Approximately 50% of people diagnosed with lung cancer are active smokers. Patients who have been diagnosed with lung cancer have been found to respond to treatment better and live longer if they quit smoking at the time of their diagnosis. They can have more difficulty getting through treatment, being at higher risk of side effects such as pneumonia and lung inflammation, which can result in needing to lower the chemotherapy doses a person receives, resulting in less effective therapy. In addition, having given up smoking decreases the chance of developing another lung cancer after treatment for the current cancer.
Smoking also has an effect on people around you. Second-hand smoke, or smoke inhaled when you are near someone smoking, is another risk factor for lung cancer. It is estimated that approximately 15% of cases of lung cancer in non-smokers are caused by second-hand smoke exposure in childhood and adolescence. Non-smoking spouses of smokers are 30% more likely than spouses of non-smokers to get lung cancer. Even though many people don't "inhale" them, smoking pipes and cigars is a risk factor for lung cancer as well. Even though you are not inhaling, you are breathing the air that is filled with the smoke from these products. The more pipes or cigars you smoke, the more likely you are to get lung cancer. Although it is not as well established as cigarette smoking, smoking marijuana is also a risk factor for getting lung cancer. Both the magnitude and duration of marijuana use seems to be related to your overall risk. Add vaping?
Radon is the second leading cause of lung cancer in the United States. Radon is a naturally occurring odorless, colorless radioactive gas that results from the decay of rock and soil components. Radon moves up from the ground into homes, where it becomes trapped and accumulates, exposing the inhabitants to its cancer-causing potential. Different areas of the world have different amounts of radon produced, but the type of foundation in your home is also important, since some foundations are better ventilated. Because of this, two homes next door to each other could have different levels of radon in the indoor air.
Radon can accumulate in new and old homes and those with OR without a basement. The only way to know if your home contains radon is to have it tested, which can be done using a kit from a hardware store or having a radon professional perform the test. Many areas have laws requiring radon testing before a house is sold. If radon is detected in levels above 4 pCi/L (picocuries per liter), you should have a removal system installed, which vents the gas to the outside using a pipe and fan system. Because it is not clear what level of radon is safe, the EPA recommends that people consider a removal system for levels from 2-4 pCi/L.
Radiation therapy for a prior cancer that includes lung tissue in the treatment field increases the risk for developing a new cancer in that area of the lung. Such secondary cancers often take a decade or longer to develop. This can be seen in people treated for Hodgkin lymphoma and breast cancer, among others. Some guidelines suggest that Hodgkin lymphoma survivors have screening for lung cancers after treatment. Modern radiation equipment and planning reduce the exposure of healthy tissue and may reduce this risk.
Although smoking cigarettes is by far the most common and important risk factor for getting lung cancer, there are some environmental exposures that increase your risk for lung cancer as well. People who work with asbestos are more likely to get lung cancer; and if they smoke cigarettes too, their risk rises even higher. Asbestos is found in industries like shipbuilding, insulation/fireproofing, and asbestos mining and production. Other workers who may have a higher risk of lung cancer are those exposed to arsenic, chromium, nickel, vinyl chloride, hard metal dusts, talc, uranium, and gasoline and diesel exhaust fumes.
People who have already had lung cancer are at risk for getting another lung cancer. A history of interstitial lung disease, pulmonary fibrosis or tuberculosis (TB) also increases your risk of getting lung cancer. However, it should be stressed that cigarette smoking is far and away the most important and dangerous risk factor for developing lung cancer.
The number of cases of lung cancer in never smokers (people who have smoked less than 100 cigarettes in their lifetime) has been increasing in many countries, including the US. Worldwide, never smokers make up 15-20% of new lung cancer cases in men, but 50% of new cases in women. Primarily, these are non-small cell lung cancers, as small cell lung cancer occurs almost exclusively in current or former smokers. Even more perplexing is how these rates vary based on geographic area – in Asia, 60-80% of women diagnosed with lung cancer are never smokers. This makes researchers think that lung cancer in never smokers may be a biologically different disease than in smokers.
The cause of these cancers is not clear, though the risk factors discussed above are all possibilities. Researchers are studying how these cancers may respond differently to targeted therapies aimed at specific molecular abnormalities and how smoking status could be used in treatment planning.
The best way to prevent lung cancer is to quit smoking, or to never start in the first place. Avoid being around people who are smoking and do not use pipes, cigars, and marijuana. Have your home tested for radon and install a removal system if needed. If you work in an industry where you are exposed to substances known to cause lung cancer, make sure to use all the proper protective equipment and attire made available by your employer.
The future of lung cancer prevention will rely on sophisticated analysis of patients' genes and molecular markers for lung cancer risk; this coupled with "smart drug" design and novel imaging techniques may one day help decrease the risk of developing lung cancer.
The National Lung Screening Trial began in 2002 and was designed to compare annual chest CT scans (a low dose spiral CT) with chest x-rays to screen high-risk patients, with the goal of improving survival by detecting lung cancer earlier. The study had 53,000 participants who were between the ages of 55 and 74 and were current or former heavy smokers, which was defined as a minimum of 30 pack year history (pack years = # of packs per day x # of years smoked). The study found that CT scan found significantly more cancerous and pre-cancerous lesions than chest x-ray. In addition, this translated into a 20% reduction in the number of deaths from lung cancer. People screened with CT scans had more areas of concern detected, which means more testing that may ultimately not turn out to be cancer (called a false positive), but experts agree that the benefits of screening in this high risk population outweigh the risks. In 2013, the US Preventive Task Force recommended annual CT screening in current or former (quit in the last 15 years) heavy smokers, ages 55-79, taking into consideration their health and ability to undergo curative surgery if a cancer is found. In 2015, the Centers for Medicare and Medicaid Services (CMS), declared Medicare would cover such CT screenings for appropriate high-risk patients. Many other insurance companies also provide coverage for this type of screening including Medicare Advantage plans, Medicaid expansion plans and private insurer plans.
Unfortunately, the early stages of lung cancer may not have any symptoms. As the tumor grows in size, it can produce a variety of symptoms including:
Many of these symptoms are non-specific, and could be caused by many non-cancerous conditions. You should see your healthcare provider if you are experiencing any of these symptoms. Most patients (approximately 85%) who are diagnosed with lung cancer have symptoms that prompt the healthcare provider to order tests to look for a problem. A cough is the most common presenting symptom of lung cancer; however, many long-term smokers have a chronic cough, so it is especially important for someone with a chronic cough to see their doctor if their cough changes in character or severity.
When someone has symptoms suggestive of a lung tumor, they will typically be referred for blood work and a chest x-ray and/or CT scan (a 3-D x-ray) of the chest. Your doctor may order sputum cytology, which means examining your phlegm for cancer cells. To see if the lung cancer has spread outside of the chest, you may have a CT scan of the abdomen and/or a PET-CT scan. To see if the lung cancer has spread specifically to the brain, you may have an MRI or CT scan of the brain.
While all of these tests are important pieces of the puzzle, a biopsy is the only way to know for sure if you have cancer. A biopsy takes a sample of the suspicious area, which is then examined under a microscope for the presence of cancer cells. In addition, the biopsy is necessary to determine the type of lung cancer and if there are cancer cells present in the lymph nodes.
A biopsy may be taken of the suspicious area in the lung and/or from lymph nodes near the lungs. Your doctor will determine which areas should be biopsied and which biopsy method is best in your case. Biopsies are often done by a lung surgeon or a pulmonologist (a doctor specializing in lung diseases), who is trained in bronchoscopy. Possible methods for obtaining a biopsy include:
In some cases, tumors cells can get into the fluid around your lungs (called pleural fluid), and your healthcare provider may want to drain off some fluid by putting a needle into the space where the fluid has collected and examine that fluid under a microscope. This is called a thoracentesis.
Once the tissue is removed, a doctor called a pathologist examines the specimen under a microscope. The pathologist determines if it is cancer or not; and if it is cancerous, they will characterize it by what type of tissue it arose from, what subtype of lung cancer it is, how abnormal it looks (known as the grade), and whether or not it is invading surrounding tissues or lymph nodes. The pathologist sends a pathology report to your provider, detailing their findings, which is an important piece in planning your treatment. You can request a copy of your report for your records.
In order to guide treatment and offer some insight into prognosis, lung cancer is staged. Healthcare providers use the TNM system (also called tumor - node - metastasis system). This system describes the size and local spread of the tumor (T), if any lymph nodes are involved (N), and if it has spread to other more distant areas of the body (M). The TNM is then converted to a stage, between 0 and IV (four), with higher numbers denoting more advanced disease.
Part of your workup is done to look for spread of the tumor (metastasis) and will probably include CT scans of the liver and adrenal glands (located above the kidneys), a CT scan or MRI (a scan that uses magnets instead of radiation) of your brain, and a PET scan. If you are having particular symptoms, your provider may want different or more specific exams to determine their cause. Stage IIIB and stage IV non-small cell lung cancers are generally considered inoperable, so it is very important to know if the cancer has spread to these more distant lymph nodes on the opposite side of the chest as the tumor or by the collarbone. Often times, your doctor will order tests called PFT's (pulmonary function tests) to assess your lung capacity prior to considering surgery, radiation therapy, and some types of chemotherapy. Overall, your providers will want to know as much about your cancer and your health as possible so that they can plan the best available treatments.
Clinical staging is done based on the size and location of the tumor on CT scans and PET scans, and if there is any evidence of spread to other organs that is picked up with radiology tests. The stage of the cancer affects how it is treated.
NCCN Guidelines for Staging of Small Cell Lung Cancer (American Joint Committee on Cancer, 7th Edition, 2010)
Small cell lung cancer is grouped into two stages for the purposes of treatment decisions:
The TNM breakdown is quite technical, but is provided here for your reference. Your healthcare provider will use the results of the diagnostic work up to assign the TNM result.
Primary Tumor (T)
|TX||Primary tumor cannot be assessed, or tumor proven by the presence of malignant cells in sputum or bronchial washing but not visualized by imaging or bronchoscopy|
|T0||No evidence of primary tumor|
|T1s||Carcinoma in situ|
|T1||Tumor 3 cm or less in greatest dimension, surrounded by lung or visceral pleura, without bronchoscopic evidence of invasion more proximal than the lobar bronchus (i.e., not in the main bronchus)|
|T1a||Tumor 2 cm or less in greatest dimension|
|T1b||Tumor more than 2 cm but 3 cm or less in greatest dimension|
|T2||Tumor with any of the following features of size or extent
|T3||Tumor >7 cm or one that directly invades any of the following:
|T4||Tumor of any size that invades any of the following:
Regional Lymph Nodes (N)
|NX||Regional lymph nodes cannot be assessed|
|N0||No regional lymph node metastasis|
|N1||Metastasis to ipsilateral peribronchial and/or ipsilateral hilar lymph nodes, and intrapulmonary nodes including involvement by direct extension|
|N2||Metastasis in ipsilateral mediastinal and/or subcarinal lymph node(s)|
|N3||Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node(s)|
Distant Metastasis (M)
|M0||No distant metastasis|
|M1a||Separate tumor nodule(s) in a contralateral lobe; tumor with pleural nodules or malignant pleural (or pericardial) effusion (when multiple cytopathologic examinations of the pleura (pericardial) fluid are negative for tumor, and the fluid is nonbloody and is not an exudate, the effusion should be excluded and the patient should be classified as M0)|
|Stage IV||Any T||Any N||M1a|
|Any T||Any M||M1b|
For many types of cancer, including NSCLC, surgery is an important part of treatment. This is not necessarily the case of small cell lung cancer. Most patients with this disease have lymph node involvement or distant metastases at the time of diagnosis. Surgery is a "local" treatment, meaning it only treats the area removed during the surgery. When cancer cells have already spread to areas outside of the lung, it is necessary to treat with a "systemic" therapy, in other words, one that can reach all areas of the body, such as chemotherapy.
The one exception to this is very early stage SCLC, where there is no cancer found in lymph nodes. In these rare cases, surgery to remove the lobe of the lung containing the tumor, combined with other therapies like chemotherapy, is the preferred treatment for patients who can tolerate the surgical procedure.
SCLC is very sensitive to the effects of chemotherapy and the majority of patients treated with chemotherapy will have a good response to initial treatment. Chemotherapy for limited stage disease is often combined with radiation therapy, and this combination has been shown to improve survival over chemotherapy alone. Unfortunately, most patients will ultimately develop resistance to chemotherapy and experience disease progression.
The chemotherapy given is most often a combination of a "platinum" medication (cisplatin or carboplatin) combined with etoposide, which is generally given in your provider's office or infusion center. The timing and number of cycles you receive will be determined by your healthcare team. This regimen is most often given in combination with radiation therapy, which can be given once daily or twice (also called hyperfractionated) daily. If given once a day, radiation therapy is typically administered over 6 to 8 weeks, and if given twice daily, is administered over 3 weeks. Radiation therapy is preferably given during the same time period as chemotherapy is being given, and it is optimally started as early after diagnosis as is feasible. However, in some cases, it may be preferable to give the radiation therapy after the chemotherapy is completed.
For patients who cannot receive the cisplatin and etoposide regimen, or have experienced a relapse after treatment, other chemotherapy that may be used include: irinotecan, paciltaxel, docetaxel, gemcitabine, topotecan, temozolomide and ifosfamide.
As with limited stage disease, SCLC is very sensitive to the effects of chemotherapy and the majority of patients treated with chemotherapy will have a good response to initial treatment. Unfortunately, most patients will ultimately develop resistance to chemotherapy and experience disease progression.
The chemotherapy given is most often a combination of a "platinum" medication (cisplatin or carboplatin) combined with irinotecan, which is generally given in your provider's office or infusion center. The timing and number of cycles you receive will be determined by your healthcare team. Some patients may benefit from receiving radiation therapy to the chest, which is given after completing chemotherapy to some patients when there was a good response to chemotherapy.
In both limited and extensive stage SCLC, patients who are doing well after treatment and have had a good response to the treatment, and the disease has not spread anywhere outside of the chest, may be offered treatment with "PCI" or prophylactic cranial irradiation. SCLC tends to spread to the brain, despite treatment with chemotherapy. Studies have found that patients treated with radiation therapy to the whole brain after completing chemotherapy have lower rates of brain metastases and improved survival rates. Patients who have had the cancer spread to the brain can also benefit from radiation therapy to the brain, with improved survival and quality of life.
Clinical trials are extremely important in furthering our knowledge of this disease. It is though clinical trials that we know what we do today, and many exciting new therapies are currently being tested. Talk to your healthcare provider about participating in clinical trials in your area.
Once you have been treated for lung cancer, you will need to be closely followed by your oncology team. At first, you will have follow-up visits fairly often. The longer you are free of disease, the less often you will have to go for checkups. The NCCN recommends seeing your healthcare provider for physical examination every 3-4 months in the first two years, every six months during years 3-5, and then annually. Your healthcare providers will order chest imaging and bloodwork as indicated. If any new pulmonary nodules appear, your healthcare provider should initiate a workup for a new primary cancer. Routine PET/CT is not recommended for follow-up care.
Quitting smoking is important in lung cancer survivorship. Remember, it is never too late to get the health benefits of smoking cessation. If your family members smoke, it is a great opportunity to support each other and quit together. There are many programs to provide support in quitting as well as medications to support your efforts as well. Talk with your provider about these resources.
Fear of recurrence, relationships challenges, financial impact of cancer treatment, employment issues and coping strategies are common emotional and practical issues experienced by lung cancer survivors. Your healthcare team can identify resources for support and management of these practical and emotional challenges faced during and after cancer.
Cancer survivorship is a relatively new focus of oncology care. With some 15 million cancer survivors in the US alone, there is a need to help patients transition from active treatment to survivorship. What happens next, how do you get back to normal, what should you know and do to live healthy going forward? A survivorship care plan can be a first step in educating yourself about navigating life after cancer and helping you communicate knowledgeably with your healthcare providers. Create a survivorship care plan today on OncoLink.
Lung Cancer Alliance
Provides support and advocacy for people living with lung cancer or at risk for the disease. www.lungcanceralliance.org
Dedicated to changing outcomes for people with lung cancer through research, education, and support. lungevity.org
American Lung Association
Information on diagnosis, treatment and support. www.lung.org/lung-disease/lung-cancer/
Facing Lung Cancer Interactive Videos
From the ALA, interactive videos to learn about treatment options and support resources. www.mylungcancersupport.org/interactive-library/
Free to Breathe
Funds research and advocates for improved treatments. Provides patients with treatment information. www.freetobreathe.org
Professional oncology social workers provide free emotional and practical support for people with lung cancer, caregivers, and their loved ones; affiliated with CancerCare. www.lungcancer.org
American Lung Association Lung Cancer Screening: Coverage in Health Insurance Plans. http://www.lung.org/assets/documents/lung-cancer/interactive-library/lung-cancer-screening-implementation.pdf
National Cancer Institute SEER Stat Fact Sheets: Lung and Bronchus Cancer http://seer.cancer.gov/statfacts/html/lungb.html
National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology: Small Cell Lung Cancer http://www.nccn.org/professionals/physician_gls/pdf/sclc.pdf
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