Lab tests of biopsy or surgery samples

Lung cancer is often diagnosed by removing a small piece (sample) of the tumor during a biopsy. Tests are then done to find out what kind of lung cancer it is.

If non-small cell lung cancer is diagnosed, special lab tests may be done on the biopsy samples. These tests are done to see if the cancer cells have certain gene changes (mutations) that help the cancer grow and spread. This is called molecular testing. It helps your healthcare provider know if targeted therapy or immunotherapy medicines will work to treat the cancer.

Imaging tests to look for cancer spread

CT scan

During a CT scan, X-rays are used to scan part of the body, such as the chest or belly (abdomen), to create detailed pictures of the inside of your body. These pictures help your healthcare provider see where the cancer is in your chest. They also show if the cancer has spread to nearby lymph nodes or to other organs near the tumor. 

MRI

An MRI scan uses magnets, radio waves, and a computer to create detailed pictures of the inside of your body. An MRI may be used to see if the cancer has spread to your bones or brain. If it has, an MRI can show the size of the tumor and how far it has spread. Sometimes a contrast dye is put into your blood before getting the scan. It helps get clearer pictures.

PET scan

A PET scan can give the healthcare provider a better idea of whether an abnormal area seen on a CT scan or other imaging test is cancer. A radioactive sugar is put into your blood before the scan. It collects in very active cells, such as cancer cells. The scan then shows where the radioactive sugar is in your body.

The PET scans your whole body. So this test is often used to look for spread of the cancer to lymph nodes or other parts of your body. A PET scan is very useful if your provider thinks the cancer may have spread, but doesn't know where. The picture is not as detailed as a CT scan, so a PET scan is often done along with a CT scan to look for tumors. 

Bone scan

A bone scan is a lot like a PET scan. But it uses a different radioactive substance that collects in changes in your bones. This may be a sign that the cancer has spread there. A bone scan looks at your whole skeleton. It's done mainly when your healthcare provider thinks the cancer may have spread to your bones, but other tests aren't clear. Bone scans aren’t often needed if you've already had a PET scan. This is because both tests tend to show the same things.

Procedures to look for cancer spread 

Endobronchial or esophageal ultrasound

These tests can be used to look for cancer that has spread to lymph nodes or other problems in the area between the lungs. This area, which is under the breastbone, is called the mediastinum.

You will be given medicine or anesthesia to keep you comfortable. A long, thin, lighted tube (bronchoscope) is used to do an endobronchial ultrasound. It's put in through your mouth or nose and into your windpipe (trachea). The bronchoscope has an ultrasound transducer at its tip. The transducer gives off sound waves and picks up the echoes as they bounce off body tissues. A computer makes the echoes into an image on a screen. The transducer can be pointed in different directions to look at lymph nodes and other structures in the mediastinum. If the healthcare provider sees suspicious areas, such as enlarged lymph nodes, a hollow needle can be passed through the scope to get biopsy samples of them. The samples are then sent to a lab for testing.

If an endobronchial ultrasound can't reach the area of concern, an esophageal ultrasound may be used instead. In this test, the scope is passed down the swallowing tube (esophagus) instead of the windpipe. It can also be used to look at lymph nodes in the mediastinum.

Mediastinoscopy or mediastinotomy

These tests can also be used to look at and biopsy lymph nodes between the lungs (in the mediastinum). An imaging test, such as a CT scan, may show enlarged lymph nodes. But a biopsy must be done to find out if they have cancer in them. 

These tests are done by a surgeon. You are given anesthesia so you are asleep and don't feel pain. A small cut is made in the front of your neck for a mediastinoscopy. A small cut is made in your chest, between your ribs, for a mediastinotomy. A thin, lighted scope with a small camera on the end is put in through the cut. It's used to look at lymph nodes under your breastbone at the center of your chest. Special tiny tools can be passed through the scope to take out tissue. The removed tissue is sent to the lab to be checked for cancer.

Bone marrow biopsy

This test is rarely used. But you may need it if the healthcare provider wants to see if the cancer has spread to the bone marrow. This is a thick, sponge-like liquid in the center of certain bones. This biopsy is done by putting a thick needle through your skin and into the back of your hip bone. Your skin and the bone is numbed first.

Working with your healthcare provider

Your healthcare provider will talk with you about which tests you'll have. Make sure to get ready for the tests as instructed. Ask questions and talk about any concerns you have.