Lung Cancer

Methods for Evaluating

Several tests are available to help your doctors learn more about your lung cancer. These tests have two important purposes: First, they provide details that help your doctors make a specific diagnosis about the type of lung cancer you have. Second, the tests offer information that helps doctors assign a stage to the lung cancer. An accurate diagnosis and stage are essential for determining the best treatment options, which may spare you from treatment unlikely to be effective. Learn how these tests are done and what you can expect (Table 1), and ask your doctor any additional questions you may have.

Table 1: Diagnostic and staging procedures: What to expect

Imaging study or procedure How it's done
Standard chest X-ray A chest X-ray is usually taken with the person standing against a plate on which the images are recorded. You must keep still and hold your breath for a few seconds when the X-ray picture is taken.
Computerized tomography (CT) A CT scanner takes many pictures of organs as the table on which you’re lying moves slowly through the scanner. You will need to lie very still while the images are being made. A contrast material (also referred to as dye) may be injected into a vein in your arm or given to you by mouth before the test to enhance the quality of the images. This contrast material may cause you to feel a brief sense of warmth or flushing in your body; this feeling is normal. If you are to receive contrast material, your doctor will order a blood test to check your kidney function to prevent possible kidney problems related to the contrast material. CT scans can be taken of portions of your body, such as your chest, abdomen or pelvis. When combined with PET scans, the entire body is usually scanned.
Positron emission tomography (PET) A small amount of a radioactive glucose (sugar) is injected into a vein. Lung cancer cells use a high amount of energy and will absorb greater amounts of the radioactive sugar than normal tissue cells do. A special camera detects any increased amounts of radioactive sugar and provides an image of the tumor or an area of metastasis.
Magnetic resonance imaging (MRI) Images are produced through radio waves and a powerful magnet linked to a computer. Although MRI is painless, you will need to lie still on a table within the tube of the MRI machine, which makes loud, repetitive clicking noises. Tell your doctor if you are uncomfortable in enclosed spaces so that steps can be taken to manage your anxiety. Contrast material may be used to enhance the images. Although any part of the body can be scanned, the brain is the most common site scanned to stage lung cancer.
Bone scan A small amount of a low-level radioactive substance is injected into a vein in your arm. This radioactive substance collects in areas of metastatic disease in bone. You will then lie on a table for about 30 minutes, and a special camera will record images of areas with an increased amount of the radioactive substance. Most of the substance will be eliminated from your body within one day and will be completely gone within two days.
Bronchoscopy A thin, tube-like instrument (bronchoscope) is inserted through the nose or mouth into the trachea (windpipe) and lungs. The bronchoscope has a light and lens that enable the doctor to examine the inside of the trachea, air passages (bronchi) and lungs. Tiny tools can also be inserted through the bronchoscope to obtain samples for pathologic evaluation. You will be lightly sedated to keep you comfortable during the procedure.
Endobronchial ultrasound A bronchoscope is inserted, and a small, special ultrasound probe is passed through the bronchoscope. The ultrasound gives off sound waves, which provide images of the lungs and mediastinal area. Tiny tools can also be inserted through the bronchoscope to obtain samples for pathologic evaluation. You will be lightly sedated or given general anesthesia to keep you comfortable during the procedure.
Mediastinoscopy A very small incision is made just above the breastbone, and a thin tube (mediastinoscope) is inserted into the incision. A tiny camera on the tube sends pictures of the mediastinal area and lungs to a video screen that the doctor can see. The video images can also help your doctor obtain samples from any areas that look abnormal. General anesthesia is usually given to keep you asleep and without pain during the procedure.

 

Diagnostic imaging studies

Imaging studies are primarily used to help define the size, shape and location of the tumor. They are also useful in assessing other parts of the body to see if the cancer has metastasized (spread beyond the lung), which aids in defining the stage of disease.

Chest X-ray

Standard chest X-rays are often the initial type of imaging study done because of their convenience and low cost. A chest X-ray is usually the first imaging study to show an area on the lung suspected to be cancer.

Computerized tomography (CT)

CT scans produce three-dimensional, cross-sectional X-ray images, so they can provide more precise details than a standard X-ray. CT scans provide an excellent assessment of the size of lymph nodes, but the size does not always indicate whether or not the nodes are involved with cancer. Because of this, other studies may be done to evaluate the lymph nodes.

Positron emission tomography (PET)

PET images are not as finely detailed as CT images, but they can provide helpful information, especially if you have early-stage lung cancer, because the scan may show that the cancer has spread to other sites. PET scans are particularly useful if your doctor thinks cancer may have spread beyond the lung but does not know where. PET scans are also helpful in distinguishing cancerous lesions from benign (noncancerous) lesions. PET scans are not helpful, however, for finding metastasis to the brain.

CT/PET

In diagnosing lung cancer, PET scans are used most often in combination with a CT scan, with the two tests done in the same testing session. The use of both tests provides a more complete picture for the radiologist, who can compare areas of higher radioactivity on the PET scan with the detailed appearance of the same area on the CT scan.

Magnetic resonance imaging (MRI)

MRI is most valuable for detecting metastasis in the brain or spinal cord. A brain MRI is commonly done in the initial staging of lung cancer and may also be done to look for metastasis in other parts of the body.

Bone scan

A bone scan helps determine whether lung cancer has spread to bone. This test is often unnecessary because PET scans, which are more commonly used for people with lung cancer, can also show if cancer has spread to bone. A bone scan is usually done only if a person has signs and symptoms of metastasis.

Staging procedures

Staging procedures allow the doctor to view the lungs and/or surrounding area and to obtain a biopsy sample from the tumor and/or nearby lymph nodes or other tissue.

Bronchoscopy

A bronchoscopy allows your doctor to look inside the lungs and the large airways in the lungs (bronchi) for abnormal areas. Tiny tools can be inserted into the bronchoscope to obtain samples of tissue or fluid.

Endobronchial ultrasound

Done using a bronchoscope, this is a newer technique that offers a way to examine the area of the chest between the lungs and the heart (mediastinum) without the need for incisions. The images provided by the ultrasound instrument help guide the doctor in removing samples for evaluation. This procedure also allows the doctor to remove tissue from the mediastinal lymph nodes to see if cancer has spread there. The tissue samples removed with this technique are relatively small, however, which can be a problem. Your doctor will need enough tissue to test for genetic abnormalities, which may be important for selecting appropriate treatment.

Mediastinoscopy

Mediastinoscopy is considered to be the best method for evaluating lymph nodes in the mediastinum, but because it requires general anesthesia, it’s usually performed only in patients with early-stage disease. The doctor can remove lymph nodes through small cuts made just above the breastbone or on the left side of the chest next to the breastbone. It’s necessary to evaluate these nodes when they appear enlarged on CT scans or have high areas of radioactivity on a PET scan. This evaluation – called mediastinal staging – is important because a small tumor may appear to be early-stage disease, but if the mediastinal lymph nodes contain cancer cells, the cancer is actually a later stage, which means the treatment approach should be different.

Evaluation of tissue samples

Samples of tissue obtained during these procedures are examined by a pathologist to see if cancer cells are present and, if so, to determine the type of cancer. The pathologist will also record the size and location of the tumor, the number of lymph nodes with cancer cells, and other important facts about the cancer. In some instances, the pathologist may not be able to identify the type because the tissue sample is too small. When this happens, another biopsy may be necessary. The pathologic evaluation of biopsy samples offers the most valuable information for the diagnosing and staging of lung cancer.

Testing for genetic abnormalities

As researchers learn more, they have discovered three genetic abnormalities that may affect how non-small cell lung cancers grow and, perhaps more importantly, how they respond to some types of treatment. These three abnormalities are mutually exclusive; that is, none is found with another in the same tumor. The genetic abnormalities differ according to the types of people and lung cancers in which they are most often found (Table 2).

Determining if any of these three genetic abnormalities is present has become an important part of diagnosing non-small cell lung cancer, especially for people with advanced disease, as treatment options may differ depending on the presence or absence of a genetic abnormality. Talk to your doctor about whether your tumor specimen should be tested for genetic abnormalities, which is also known as molecular testing.

Table 2: Genetic abnormalities in non-small cell lung cancer

Genetic abnormality Most commonly found Type of non-small cell lung cancer Advisability of testing
EGFR mutation
▪  Women
▪  People who never have
   smoked
▪  People of Asian    descent
▪  Light smokers
All types, but most often in adenocarcinoma and rarely in squamous cell carcinoma Recommended
ALK rearrangement
▪  Younger people
▪  People who never    smoked or light    smokers
Adenocarcinoma Recommended
KRAS mutation
▪  Current or former    smokers
All types, but most often in adenocarcinoma and less often in squamous cell carcinoma Increasingly being done in many medical centers; may help to select patients who do not require further testing

 

Additional Resources

 

Previous Next

 



Register Now! Sign Up For Our Free E-Newletter and Receive a FREE Bracelet!

Read Inspiring Cancer Survivor Stories

Order Your Guides Here