Helen Tosch; Types of Lung Cancer; Northwestern Memorial
Lung Cancer Overview and Disease Information Can Be Found At: http://www.nmh.org/nm/lung+cancer
Overview
Lung cancer is a disease that begins in the lungs. The lungs are sponge-like organs in the chest that take in oxygen when
you inhale and release carbon dioxide when you exhale. When lungs work properly, oxygen is processed in the lungs and
sent to the rest of the body through the blood. That oxygen is vital to functioning and survival. Carbon dioxide, a waste
product of our cells, is released from the body upon exhalation. Exchanging carbon dioxide for oxygen is another
critically important function of the lungs.
Guide to Lung Cancer Screening
The National Lung Cancer Screening Trial is the first scientific study that provides clear evidence that low-dose helical
CT scan is an effective screening technique and significantly reduces death due to lung cancer in heavy smokers. Read
more about this groundbreaking study.
Lung cancer develops when a cell in the lung becomes abnormal and begins to duplicate itself. When abnormal cells
duplicate, they will eventually form a mass of cells, known as a tumor. The tumor cells can invade locally through the
lung tissue and into adjoining structures like the ribs. Tumor cells can also travel through lymph vessels or the
bloodstream to other parts of the body. When cancer cells spread from their original location to another part of the body, it
is considered metastasis. Lung cancer typically spreads (metastasizes) through the blood and lymph nodes.
Types of Lung Cancer
There are two major categories of lung cancer – non-small cell (approximately 85% of all lung cancers) and
small cell (about 10% ). A smaller percentage of lung cancers are called carcinoid tumors.
Non-Small Cell
Non-small cell lung cancer is a term that includes several types of cancer that behave similarly. Each type is
made up of different kinds of cancer cells that grow and spread in different ways.The types of non-small cell
cancers include:
Adenocarcinoma
Cancer that begins in the glandular cells that line the small airways and tiny air sacs inside the lungs (alveoli)
and produce substances, such as mucus, in the lungs
Bronchioloalveolar cell carcinoma (BAC)
A slower growing subtype of adenocarcinoma
Squamous cell carcinoma
Cancer that begins in the squamous cells, which are thin, flat cells that look a bit like scales on a fish; it is also
known as epidermoid cancer
Large cell carcinoma
Cancer that tends to begin in several types of large cells within the lung
There are a number of less common types of non-small cell lung cancer. They are:
Carcinoid tumor
Pleomorphic carcinoma
Adenoid cystic carcinoma
Large-cell-neuroendocrine carcinoma (LCNEC)
Adenosquamous carcinoma
Poorly-differentiated carcinoma
Unclassified carcinoma
Small Cell (aka Oat Cell Carcinoma)
Small cell lung cancer involves cancer cells that are smaller in size than most other types of cancer cells. It is
different from non-small cell lung cancer in the size of the cancer cells and the ways the cells grow and spread.
Although the cells involved in small cell lung cancer are small, they are able to reproduce very rapidly, so they
often produce large tumors, and they are able to easily spread to the lymph nodes and other areas of the body.
Carcinoid
Carcinoid lung tumors are the least common type of lung cancer. These are low-grade cancers with slower
tumor growth and infrequent metastases to local lymph nodes. They are different from non-small cell and small
cell lung cancer in that the tumor begins in the hormone-producing cells within the lung. Carcinoid tumors can
also begin in other organs in the body. The digestive tract, specifically the small intestine and the rectum, are
the most common places to find carcinoid tumors.
Carcinoid tumors are typically slow growing, and they often do not produce symptoms until they have been
growing for many years. The tumors are cancerous, but because they are slow growing, they are often curable.
There are two main types of carcinoid lung cancers. They are:
Typical
Atypical
In the United States, approximately 3,000 adults will be diagnosed with carcinoid lung tumors every year. The
overall five-year survival rate is 85 to 90 percent for people diagnosed and treated appropriately for typical
carcinoid tumors of the lung and 50 to 60 percent for those diagnosed with atypical carcinoid tumors. Please
consider, however, that all cancer survival statistics should be interpreted with caution.
Symptoms
The most common symptoms of both small cell and non-small cell lung cancer are coughing, chest pain and
shortness of breath. However, any of the following symptoms may be signs of lung cancer or other lung disease
and should be evaluated by a doctor.
A cough that doesn’t go away
Changes in a chronic or “smokers” cough (more commonly seen in non-small cell cancer)
Breathing difficulty or shortness of breath
Chest discomfort or pain
Wheezing
Coughing up blood – even a small amount
Hoarse voice
Appetite loss
Unexplained weight loss
Feeling fatigued or overly tired
Causes
The majority of lung cancer is caused by smoking. It is one cancer for which we have biochemical evidence
linking the carcinogens in tobacco products with the development of cancer. We also know how people can
drastically reduce their risk of getting lung cancer. Never starting to smoke or quitting smoking are the best
ways to reduce your chances of getting lung cancer.
Learn more about smoking cessation and classes through Northwestern Memorial Hospital.
Although most people who get lung cancer are smokers, people who used to smoke, and people who had
significant exposure to secondhand smoke, there is a small percentage of people with lung cancer who never
smoked nor had prolonged exposure to smoke. In these cases, there may not be a clear, identifiable cause of
cancer, but there are some risk factors that have been associated with development of lung cancer. They are:
Exposure to uranium
Exposure to radon
Exposure to certain chemicals and carcinogens
Exposure to asbestos in the absence of smoking can lead to a different chest malignancy called mesothelioma.
When combined with smoking, asbestos exposed patients do have a higher risk of developing lung cancer.
The lung can also serve a site of spread from other types of cancers, meaning a cancer that began somewhere
else in the body spreads via the bloodstream to the lungs. These are called secondary or metastatic tumors.
Risk Factors
Smoking cigarettes, pipes or cigars is the most common cause of lung cancer. The amount of smoking increases
a person’s risk. A person who smokes two packs a day for 20 years has a greater risk than someone who
smoked occasionally for a few years, but all smokers and people exposed to significant second hand smoke
have an elevated risk – regardless of the amount of time they smoked or were exposed to smoke. Though risk
doesn’t disappear when a person stops smoking, it does decrease as the years pass.
Risk factors for disease include anything that increases a person’s chance for developing a disease. However,
having a risk factor doesn’t mean you’ll get the disease, and not having any risk factors does not mean you
won’t get a disease. While smoking has been proven biochemically to cause lung cancer, other risk factors are
simply more commonly observed in patients who develop cancer without establishing them as causing the
disease. Risk factors for lung cancer are:
Smoking cigarettes, pipes or cigars, now or in the past
Being exposed to second-hand smoke
Being treated with radiation therapy to the breast or chest
Being exposed to asbestos, radon, chromium, nickel, arsenic, uranium, soot or tar
Reducing Your Risk
Quitting smoking, or never starting to smoke, is the single best way to reduce your risk for lung cancer, other
lung and throat diseases, and the many diseases and conditions caused by or related to smoking. If you smoke,
we urge you learn more about how to successfully quit.
Learn more about smoking cessation and classes through Northwestern Memorial Hospital.
Lung Cancer Screening
Lung cancer is one of the most common forms of cancer in the United States, and the leading cause of death
from cancer. Often, lung cancers grow silently for many years and reach an advanced stage before causing
symptoms that lead to diagnosis and treatment. Until recently, no screening test for lung cancer has proven
effective in detecting tumors at an early, more treatable stage.
The National Lung Cancer Screening Trial
The National Lung Cancer Screening Trial (NLST) is a national cancer screening trial sponsored by the
National Cancer Institute (NCI) and conducted by the American College of Radiology Imaging Network
(ACRIN) and the Lung Cancer Study Group. The trial compared two methods of detecting lung cancer:
Standard Chest X-ray
Low Dose Helical (Spiral) Computed Tomography (CT)
The trial included more than 53,000 “heavy smoker” adults at 33 sites throughout the country. Each participant
was either a former heavy smoker within the last 15 years or a current smoker with at least a 30 pack year
history of smoking*. Between 2002 and 2007, these individuals were randomly assigned to receive either a
standard chest x-ray or a helical CT scan annually for three years.
* Pack years is a term used to categorize smoking history. To calculate smoking pack years, multiply the
number of packs smoked each day times the years of smoking. For example, a person who has smoked 2 packs
per day for 15 years has a 30 pack year smoking history.
Northwestern Memorial Hospital and the NLST
Northwestern Memorial was the only NLST site in Chicago. Eric M. Hart M.D., an attending radiologist at
Northwestern Memorial Hospital and Associate Professor of Radiology at Northwestern Feinberg School of
Medicine, was the principal investigator for the NLST at Northwestern Memorial.
More than 400 adult smokers between the ages of 55 and 74 years were enrolled in the NLST at Northwestern
Memorial. These participants were assigned randomly to receive one of the two screening techniques for three
years, followed by monitoring for the next five years.
Results of the NLST
Initial results of the NLST were released publically November 4, 2010. They showed a statistically significant
benefit for the study participants who were screened using helical CT. There were 20% fewer lung cancer
deaths among the individuals at high risk for lung cancer who had been screened with CT scans as compared
with those who were screened with standard chest X-rays.
The NLST is the first scientific study that provides clear evidence of an effective screening technique that
significantly reduces death due to lung cancer in heavy smokers. A full set of study results is expected to be
published in Spring 2011.
Reducing Your Risk for Lung Cancer
If you are a current smoker, the most important way to reduce your chances of getting lung cancer is to stop
smoking. Tobacco use causes lung cancer, chronic lung disease, and cardiovascular disease. The longer you
continue to smoke, the higher your risk for developing one of these diseases. More importantly, if you stop
smoking, damage from tobacco may be partially reversible.
At Northwestern Memorial, we offer smoking cessation classes to help you find a way to quit smoking. For
more information about group or individual programs to quit smoking, visit our Web site at
nmh.org/nm/smoking cessation.
Should All Smokers Get a CT Scan to Screen for Lung Cancer?
Based on the NLST results, the following individuals at high risk for lung cancer will benefit from CT scan
screening:
Men and Women between the ages of 55 and 75 years, AND
Current or former heavy smokers (≥ 30 pack years)
If you think you are a candidate for a CT scan to screen for lung cancer, please talk with your doctor about the
benefit of CT screening for your particular circumstance.
Important factors to consider include:
Medicare and other insurers do not pay for CT lung cancer screening at this time.
Screening CT scans do not find all lung cancers.
CT scans in current or former smokers often show abnormal areas (such as scar tissue or inflammation)
that are suspicious for lung cancer and require additional testing to make an accurate diagnosis.
It is important to contact your doctor if you have any worrisome signs or symptoms, such as weight loss
of more than 15 pounds, persistent respiratory infection, or coughing up blood.
For More Information About the National Lung Cancer Screening Trial
Visit the National Cancer Institute Web site: cancer.gov/nlst/updates.
Tests & Diagnosis
There are a number of tests and procedures that can be used to detect, diagnose and stage lung cancer. If your
physician suspects you may have lung cancer or lung disease based on your symptoms and risk factors, he or
she may recommend tests and procedures that can confirm or rule out cancer. Some of the most commonly used
are:
Imaging Tests
Imaging tests are often used to aid in the diagnosis of lung cancer. The most commonly used tests include:
Chest X-ray
Chest X-rays are simple images of the chest that may be able to reveal abnormal masses or nodules in the lung.
CT scan (computed tomography scan)
CT scans involve taking a series of detailed, cross-sectional images of areas of the body. When testing for lung
cancer, the CT scan would be of the chest. Chest CT scan images are reformatted by a computer to generate two
and three-dimensional renderings of the lungs and are often able to reveal small lesions in the lung that may not
be caught on a chest X-ray.
PET scan (positron emission tomography scan)
PET scans use radioactive glucose that is injected into a vein to look for cancer masses. Cancerous tumors are
more active than normal cells, so they take up more glucose than the normal cells. When the glucose is taken up
into tumors and the PET scanner takes photos of the area being scanned, the images will reveal brighter areas
where the tumors reside, due to the increased uptake of glucose.
Sputum Cytology
Sputum is the medical word for mucus that has been coughed up from the lungs. Sputum cytology is a test of
the sputum that involves looking at the sputum under a microscope for the presence of cancer cells.
Tissue Sampling (Biopsy)
There are a number of ways to check tissue samples for the presence of lung cancer. The most common
procedures are:
Fine-needle aspiration (FNA) biopsy of the lung
During a fine-needle aspiration (FNA), a thin needle is used to remove tissue or fluid from the lung. During the
FNA, physicians use imaging procedures, such as a CT scan or ultrasound, to find the abnormal tissue or fluid.
Once it is located, they insert the biopsy needle into the tissue or fluid, and a sample is removed for testing. That
biopsied fluid or tissue is then sent to a laboratory to be tested for the presence of cancer cells.
Bronchoscopy
A bronchoscopy involves looking for abnormal areas inside the trachea (windpipe) and the central bronchi
(large airways) in the lungs. During the procedure which is performed under light sedation, a lighted, flexible
tube-like instrument is placed through the nose or mouth into the trachea and lungs, allowing physicians or
surgeons to visualize the areas. If any abnormalities are found or suspected, surgeons can also remove tissue
samples during the procedure. Any tissue samples are then checked for signs of cancer.
Statistics
It may surprise many people to know that lung cancer is the leading cause of cancer death among every ethnic
group in the United States. It causes one out of every three cancer deaths, and it claims more lives than breast,
colon, prostate, liver, kidney and melanoma cancers combined.
Lung cancer is the most common type of cancer in the U.S. This year alone, approximately 200,000 people will
be diagnosed with lung cancer, and more than 180,000 people will die from the disease. On average, more than
430 people will die every day from lung cancer in the United States alone.
Though it is more easily treatable in the early stages, lung cancer is unfortunately most commonly diagnosed in
later stages when it is difficult to treat. In the United States, only 16 to 20 percent of lung cancer is being
diagnosed in its earliest and most curable stage. However, it doesn’t have to be that way. Lung cancer is often
detectable through tests at early stages, sometimes before any symptoms are present. If you are at risk for lung
cancer, we urge you to talk with your doctor about your risk factors, screening options for you, and what you
can do to reduce your risk.
Quitting smoking, or never starting to smoke, is the single best way to reduce your risk for lung cancer, other
lung and throat diseases, and the many diseases and conditions caused by or related to smoking. If you smoke,
we urge you learn more about how to successfully quit.