How is small cell lung cancer found?

It is often hard to find lung cancer early. Most people with early lung cancer do not have any symptoms, so only a small number of lung cancers are found at an early stage. When lung cancer is found early, it is often because of tests that were being done for something else.

Screening is the use of tests or exams to find a disease like cancer in people who don’t have any symptoms of that disease. Doctors have tried for many years to find a test that could find lung cancer early and help patients live longer, but only in recent years has a study shown that a lung cancer screening test can help lower the risk of dying from this disease for some people. Still, small cell lung cancer tends to spread very early, and so most lung cancers that are found early are the non-small cell type.

The National Lung Screening Trial

The National Lung Screening Trial (NLST) was a large clinical trial (study) that that looked at a type of CT scan known as low-dose CT to screen for lung cancer. CT scans of the chest give more detailed pictures than chest x-rays and are better at finding small changes in the lungs. They are often used to look for cancer in patients with symptoms. Low-dose CT (LDCT) of the chest uses lower amounts of radiation than a standard chest CT. Also a contrast dye is not needed.

The NLST compared LDCT of the chest to chest x-rays in people at high risk of lung cancer to see if these scans could help lower the risk of dying from lung cancer. People in the study were current or former heavy smokers aged 55 to 74 who had no symptoms of lung cancer and who were in fairly good health.

To get in the study, a person had to have at least a 30 pack-year history of smoking. Doctors often use pack-years to describe a patient’s smoking history. To find out how many pack-years you have smoked, multiply the number of packs of cigarettes you smoke each day by the number of years you have smoked. Someone who smoked a pack of cigarettes per day for 30 years has a 30 pack-year smoking history, as does someone who smoked 2 packs a day for 10 years and then a pack a day for another 10 years.

People in the study got either 3 spiral LDCT scans or 3 chest x-rays, each a year apart. They were then followed for several years to see how many people in each group died of lung cancer. The study found that people who got spiral LDCT had a 20% lower chance of dying from lung cancer than those who got chest x-rays.

Screening with LDCT scans is also known to have some downsides that need to be taken into account. One drawback of this test is that it also finds a lot of things that turn out not to be cancer but that still need to be tested to be sure. For some people, this may lead to further, sometimes unnecessary, tests such as other CT scans, or more invasive tests such as biopsies, or even surgery to remove a portion of lung. These tests can sometimes lead to problems like a collapsed lung or, rarely, death, even in people who do not have cancer (or who have very early stage cancer). LDCT scans also expose people to a small amount of radiation with each test. While it is less than the dose from a standard CT, it is more than the dose for a chest x-ray.

While the NLST was a large study, there are some questions that still need to be answered. For instance, it’s not clear whether screening with LDCT scans would have the same effect on different groups of people, like those who smoked less (or not at all) or people younger than age 55 or older than 74. It’s also not yet clear what the effect would be if people were screened for longer than 2 years. Plus, the lung cancers that were found early were the non-small cell type, so it is not yet clear how to find small cell lung cancer early.

These factors, and others, need to be taken into account by people and their doctors who are thinking about whether screening with low dose CT scans is right for them.

For more details about the NLST, please see “Can small cell lung cancer be found early?” in our document Lung Cancer (Small Cell).

American Cancer Society’s guidelines for lung cancer screening

The American Cancer Society has thoroughly reviewed the subject of lung cancer screening and issued guidelines that are aimed at doctors and other health care providers:

Patients should be asked about their smoking history. Patients who meet ALL of the following criteria may be candidates for lung cancer screening:

• 55 to 74 years old,

• in fairly good health (this is discussed further down),

• have at least a 30 pack-year smoking history (this was discussed above), AND

• are either still smoking or have quit smoking within the last 15 years,

These criteria were based on what was used in the NLST.

Doctors should talk to these patients about the benefits, limitations, and potential harms of lung cancer screening. Screening should only take place at facilities that have the right type of CT scan and that have a great deal of experience in low-dose CT scans for lung cancer screening. The facility should also have a team of specialists that can provide the appropriate care and follow-up of patients with abnormal results on the scans.

More details about the American cancer Society’s lung cancer screening guidelines can be found in “Can small cell lung cancer be found early?” in our document Lung Cancer (Small Cell).

For patients

If you fit the all of the criteria for lung cancer screening listed above, you and your doctor should talk about starting screening. The doctor will talk to you about what you can expect from screening, including likely benefits and harms, as well as the limits of screening.

The main benefit is a lower chance of dying of lung cancer, which accounts for many deaths in current and former smokers. Still, it is important to be aware that, as with any type of screening, not everyone who takes part will be helped. Screening with LDCT will not find all lung cancers, and not all of the cancers that are found will be found early. Even if a cancer is found by screening, you might still die from lung cancer. Also, LDCT often finds things that turn out not to be cancer but that have to be checked out with more tests to know what they are. This can mean more CT scans, or even invasive tests in which a piece of lung tissue is removed with a needle or in surgery. These tests have risks of their own (see above).

At this time, most insurance programs (including Medicare) are not likely to cover an LDCT done for lung cancer screening.

Screening should only take place where there is the right type of CT scanner and that has a great deal of experience in low-dose CT scans for lung cancer screening. The facility should also have a team of experts that can provide the right kind of care and follow-up of patients whose results are not normal on the scans. The right kind of facility may not be in nearby, so you may need to travel some distance away to be screened.

If you and your doctor decide that you should be screened, you should get an LDCT every year until you reach the age of 74, as long as you remain in good health.

If you are a current smoker, you should receive counseling about stopping. You should be told about your risk of lung cancer and referred to a quit smoking program. People who smoke should keep in mind that the best way to avoid dying from lung cancer is to stop smoking. Screening does not take the place of stopping smoking. For help quitting smoking, see our document called Guide to Quitting Smoking or call the American Cancer Society at 1-800-227-2345.

What does “in fairly good health” mean?

Screening is meant to find cancer in patients who do not have symptoms of the disease. Patients who have symptoms of lung cancer (like coughing up blood and weight loss without trying) may need tests to find the underlying cause, which in some cases may be cancer. This kind of testing is for diagnosis and is not the same as screening.

Metal implants in the chest and back (like pacemakers or rods in the spine) can hamper x-rays and lead to poor CT pictures of the lungs. People with these types of implants were also kept out of the NLST, and so, according to the ACS guidelines, they should not be screened with CT scans for lung cancer.

In order to get the most benefit from screening, patients need to be in good health. For instance, they need to be able to have surgery and other treatments to cure any cancers that are found. That is why patients who need home oxygen and people with other serious medical problems might not be able to benefit enough from screening for it to be worth the risks, and so they should also not be screened.

Common signs and symptoms of lung cancer

Most lung cancers do not cause symptoms until they have spread, but you should report any of the following problems to your doctor right away. Often these problems are caused by something other than cancer. If lung cancer is found, getting treatment right away might mean your cancer could be cured. Or you could live longer with a better quality of life. The most common symptoms of lung cancer are:

• A cough that does not go away or gets worse
• Chest pain, often made worse by deep breathing, coughing, or laughing
• Hoarseness
• Weight loss and loss of appetite
• Coughing up bloody or rust-colored sputum (spit or phlegm)
• Shortness of breath
• Feeling weak or tired
• Infections such as bronchitis and pneumonia that don’t go away or keep coming back
• New onset of wheezing

When lung cancer spreads to distant organs, it may cause:

• Bone pain (like pain in the back or hips)
• Weakness or numbness of the arms or legs
• Headache, dizziness, balance problems, or seizure
• Yellow coloring of the skin and eyes (jaundice)
• Lumps near the surface of the body, caused by cancer spreading to the skin or to lymph nodes in the neck or above the collarbone

If you have any of these symptoms, you should see a doctor right away.

Some lung cancers can cause a group of symptoms called syndromes.

Horner syndrome

Cancers of the top part of the lungs (sometimes called Pancoast tumors) may damage a nerve that passes from the upper chest into your neck. This can cause severe shoulder pain. Sometimes these tumors also cause a group of symptoms called Horner syndrome:

• Drooping or weakness of one eyelid
• Having a smaller pupil (dark part in the center of the eye) in the same eye
• Reduced or absent sweating on the same side of the face

Conditions other than lung cancer can also cause Horner syndrome.

Superior vena cava syndrome

The superior vena cava (SVC) is a large vein that carries blood from the head and arms back to the heart. It passes next to the upper part of the right lung and the lymph nodes inside the chest. Tumors in this area may push on the SVC, which can cause the blood to back up in the veins. This can cause swelling in the face, neck, arms, and upper chest (sometimes with a bluish-red skin color). It can also cause headaches, dizziness, and a change in mental function if it affects the brain. While SVC syndrome can come on slowly over time, in some cases it can become life-threatening, and needs to be treated right away.

Paraneoplastic syndromes

Some lung cancers may make hormone-like substances that enter the bloodstream and cause problems with other tissues and organs, even though the cancer has not spread to those tissues or organs. These problems are called paraneoplastic syndromes. Sometimes these syndromes may be the first symptoms of lung cancer. Because the symptoms affect other organs, patients and their doctors may suspect at first that something other than lung cancer is causing them.

Most of the symptoms listed here are more likely to be caused by something other than lung cancer. Still, if you have any of these problems, you should see a doctor right away.

If your doctor thinks you might have lung cancer

After asking questions about your health and doing a physical exam, your doctor might want to do some of the following tests:

Imaging tests

There are a number of different tests that can make pictures of the inside of your body. Some of these are used to find lung cancer, to see if it has spread, to find out whether treatment is working, or to spot a cancer that has come back after treatment.

Chest x-ray: This is often the first test your doctor will do to look for any spots on the lungs. It is a plain x-ray of your chest. If the x-ray is normal, you most likely do not have lung cancer. If anything does not look normal, the doctor may order more tests.

CT scan (computed tomography): A CT (or CAT) scan uses x-rays to produce detailed cross-sectional pictures of your body. The CT scanner takes many pictures as it moves around you. A computer then combines these pictures into a detailed picture of a slice of your body.

Before the CT scan, you may be asked to drink a special liquid or you may have an IV (intravenous) line through which you are given a "dye." This helps better outline structures in your body. The dye may cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives. Rarely, more serious problems like trouble breathing or low blood pressure can happen. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays.

CT scans take longer than regular x-rays. You need to lie still on a table while they are being done. You might feel a bit confined by the ring-shaped machine you have to lie in while the pictures are being taken.

The CT scan will give the doctor exact information about the size, shape, and place of a tumor. It can also help find swollen lymph nodes that might contain cancer. CT scans are also used to find tumors in other organs that might be the spread of lung cancer.

In cases where the doctor suspects that the cancer lies deep within the body, a CT scan can be used to guide a biopsy needle right into the that place. For this, you stay on the CT scanning table while the doctor moves a biopsy needle through the skin and toward the mass. Once the doctor can see that the needle is within the mass, a piece of it is removed and looked at under a microscope.

MRI scan (magnetic resonance imaging): Like CT scans, MRI scans give detailed pictures of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. MRI scans take longer than x-rays − often up to an hour. Also, you have to be placed inside a tube-like machine, which upsets some people. Newer, open MRI machines can sometimes help with this if needed. MRI scans are useful in finding lung cancer that has spread to the brain or spinal cord.

PET scan (positron emission tomography): For a PET scan, a form of radioactive sugar is injected into the blood. Cancer cells in the body take in large amounts of the sugar. A special camera can then spot the radioactivity. This test can show whether the cancer has spread to the lymph nodes or other parts of the body. It is also helpful in telling whether a spot on your chest x-ray is cancer. Some machines combine a CT and a PET scan to even better pinpoint tumors. This is the type of PET most often used in small cell lung cancer patients.

Bone scan: For a bone scan a small amount of radioactive substance is put into your vein. The amount used is very low and it causes no long-term effects. This substance builds up in areas of bone that may not be normal because of cancer. These will be seen on the bone scan pictures as dense, gray to black areas, called "hot spots." While these areas may suggest the presence of metastatic cancer, other problems can also cause hot spots.

Bone scans are done mainly when there is reason to think the cancer may have spread to the bones (because of symptoms such as bone pain) and other test results aren't clear. PET scans can usually show the spread of cancer to bones, so bone scans aren't usually needed if a PET scan has already been done.

Other tests used to find lung cancer and its spread

The tests described below can be used to be sure that something seen on an imaging test is really lung cancer. These tests are also used to find out the exact type of lung cancer and how far it may have spread.

Bronchoscopy: A lighted, flexible tube (called a bronchoscope) is passed through the mouth or nose and into the larger airways of the lungs. The mouth and throat are sprayed first with a numbing medicine. You may also be given medicine through an intravenous (IV) line to make you feel relaxed. This test can help see tumors, or it can be used to take samples of tissue or fluids to see if cancer cells are present.

Endobronchial ultrasound: Ultrasound is a test that uses sound waves to make pictures of parts of your body. For endobronchial ultrasound, a bronchoscope is fitted with an ultrasound device at its tip and is passed down into the windpipe to look at nearby lymph nodes and other structures in the chest. This is done with numbing medicine and light sedation. If areas of concern (such as swollen lymph nodes) are seen on the ultrasound, a hollow needle can be passed through the bronchoscope and guided by ultrasound into the area to take biopsy samples. The samples are then looked at under a microscope to see if there are cancer cells.

This test may be used if the doctor is thinking about surgery as a part of treatment, which is not often the case for small cell lung cancer.

Endoscopic esophageal ultrasound (EUS): This test is much like an endobronchial ultrasound, except an endoscope (a lighted, flexible tube) is used. It is passed down the throat and into the esophagus (the swallowing tube that connects the throat to the stomach). The esophagus lies just behind the windpipe. This test is done with numbing medicine and drugs to help you relax (this is called light sedation).

Ultrasound images taken from inside the esophagus can help find large lymph nodes inside the chest that might contain lung cancer. If areas of concern (such as swollen lymph nodes) are seen on the ultrasound, a hollow needle can be passed through the endoscope to get biopsy samples of them. The samples are then looked at under a microscope to see if they contain cancer cells.

This test may be used if the doctor is thinking about surgery as a part of treatment, which is not often the case for small cell lung cancer.

Mediastinoscopy and mediastinotomy: Both of these tests may be done so the doctor can look at and take samples of the structures in the area between the lungs (this area is called the mediastinum). They are done in an operating room while you are in a deep sleep (under general anesthesia). The main difference between the two is in the place and size of the cut (incision) needed to look into this area.

Thoracentesis: This test is done to check whether fluid around the lungs is caused by cancer or by some other problem, such as heart failure or an infection. First, the skin is numbed and then a hollow needle is placed between the ribs to drain the fluid. The fluid is checked for cancer cells.

Thoracoscopy: For this test, drugs are used to put you to sleep, and a small cut is made in your chest. The doctor then uses a thin, lighted tube connected to a video camera and screen to look at the space between the lungs and the chest wall. By doing this, the doctor can see any cancer deposits on the lung or the lining of the chest wall and take out small pieces of tissue to be looked at under the microscope. Thoracoscopy can also be used to get samples of lymph nodes and fluid and to tell whether a tumor is growing into nearby tissues or organs.

Bone marrow aspiration and biopsy: These two tests are usually done at the same time. For these tests you lie on your side or on your belly. The skin over the back of your hip is cleaned. After the area is numbed, a thin, hollow needle is inserted into the hip bone to suck out (aspirate) a small amount of fluid from the marrow. A larger needle is then used to remove a small piece of the hip bone and some marrow. Even with the numbing medicine, most patients still have some brief pain when the samples are removed. The samples are then checked for cancer cells. This is done in some patients to be sure that the cancer has not spread to the bone marrow.

Sampling tissues and cells

Symptoms and the results of imaging tests may strongly suggest that lung cancer is present, but the final diagnosis of lung cancer is made by looking at lung cells under a microscope. The cells can be obtained in different ways. One or more of the tests below may be used to find out if a lung mass seen on imaging tests is indeed lung cancer. These tests can also be used to tell the exact type of lung cancer you have and to help figure out how far it may have spread.

A doctor (called a pathologist) who is an expert in using lab tests to diagnose diseases like cancer will look at the cells under a microscope. The results will be described in a pathology report, which should take about a week. If you have any questions about your results or any other tests, be sure and ask your doctor. If needed, you can get a second opinion by having your tissue sample sent to a pathologist at another lab.

Sputum cytology: A sample of sputum (mucus you cough up from the lungs) is looked at under a microscope to see if cancer cells are present.

Fine needle biopsy (FNA): For this test, a long, thin (fine) needle is put into the place in the lung that might be cancer to remove a sample of cells. (The skin where the needle is to be put in may first be numbed with medicine.) The sample is looked at in the lab to see whether there are cancer cells. An FNA biopsy may also be done to take samples of lymph nodes around the windpipe (trachea) and the larger tubes that carry air to the lungs (bronchi). (In some cases, if the results aren't clear, a larger needle may be used to remove a slightly bigger piece of lung tissue. This is known as a core needle biopsy.)

Sometimes, air may leak out of the lung at the biopsy site and into the space between the lung and the chest wall. This can cause part of the lung to collapse and may cause trouble with breathing. This often gets better without any treatment. If not, a small tube is put into the chest space and the air is sucked out over a day or two, after which it should heal on its own.

Lab tests of biopsy and other samples

Samples from biopsies or other tests are sent to a lab. There, a doctor looks at the samples under a microscope to find out if they contain cancer and if so, what type of cancer it is. Special tests may be needed to help classify the cancer. Cancers from other organs can spread to the lungs, so it is very important to find out where the cancer started so the right treatment can be given.

Blood tests

Blood tests are not used to find lung cancer, but they are done to get a sense of a person's overall health. A complete blood count (CBC) shows whether your blood has normal numbers of different cell types. This test will be done often if you are treated with chemotherapy because these drugs can affect the blood-forming cells of the bone marrow. Other blood tests can spot problems in different organs like the kidneys, liver, and bones.

Pulmonary function tests

There are different types of pulmonary function tests but they all basically involve having you breathe in and out through a tube that is connected to different machines. As a rule, they are only needed if surgery might be an option in treating the cancer. Since surgery is rarely used to treat small cell lung cancer, these tests are not often done for patients known to have small cell lung cancer.