Diagnosing Small Cell Lung Cancer

Your lungs are the two large organs located in the chest that enable you to breathe. As you inhale, air travels in through the nose and mouth, into the trachea, also known as the windpipe.

The trachea divides into two airways, called the right bronchus and left bronchus, or bronchi, which lead to the lungs’ spongy tissue. The bronchi divide into increasingly smaller breathing passages. The smallest ones are called bronchioles and lead to groups of small air sacs called alveoli, which absorb the oxygen from the air and release the carbon dioxide.

The lungs are divided into sections called lobes. There are two lobes in the left lung and three lobes in the right lung. The lungs are surrounded by the pleural cavity, which consists of a thin lining of membranes, called pleura, that are filled with a small amount of fluid. The pleura enable the lungs to move without friction as they expand and contract within the chest.

There are two main types of lung cancer. Small cell cancer accounts for about 15 percent of all lung cancers, and the remaining 85 percent are non-small cell lung cancers. Small cell tumors tend to grow more rapidly than the non-small cell variety.

Both are named for how their cells look under a microscope. Small cell lung cancer cells are small and oval. The cancer tends to start in the bronchi and rapidly spread to other organs. Most of the time, the cancer has spread beyond the lungs by the time it’s diagnosed.

People with early small cell lung cancer often don’t have any symptoms, which is why screening for lung cancer is important if you’re at high risk. When symptoms do develop, they may include an ongoing cough, chest pain, hoarseness, coughing up blood, and difficulty breathing.

If you are experiencing any symptoms, or if a screening CT scan reveals a suspicious growth, our doctors may recommend further imaging tests and a biopsy, in which a small amount of tissue is removed and examined under a microscope.

In a CT scan, X-rays produce detailed, three-dimensional, cross-sectional images of the lungs and surrounding tissues on a computer monitor. In addition to detecting suspicious growths, the scan can also show whether lymph nodes—small immune system glands that trap foreign invaders such as viruses and bacteria—are enlarged. This may mean that the nearby lymph nodes also contain cancerous cells. Before the scan, doctors may give you a contrast solution to enhance the images. It may be given either as a liquid or an injection into a vein.

If doctors find a growth that they suspect is cancerous, they may follow up with a PET/CT scan. The CT portion of this combined scan uses X-rays to create detailed, cross-sectional images of the body, and the PET scan uses a special camera to determine how rapidly cells are growing, via a small amount of radioactive glucose injected into a vein. This glucose, or sugar, collects in cancer tissue.

A PET/CT scan can help doctors determine whether a growth contains cancer and, if so, how aggressive it is. The scan can also reveal whether the cancer has spread throughout the body.

While imaging tests indicate that lung cancer may be present, only a biopsy can confirm it. In a biopsy, pathologists—doctors who study diseases in a laboratory—examine tissue under a microscope to determine the size and shape of the cells and whether they look like small cell lung cancer. Our specialists use several techniques for performing biopsies to diagnose small cell lung cancer.

CT-guided Biopsy

Doctors may use CT-guided biopsy to remove tumor tissue when a growth can be easily reached from outside the body, rather than from within the passageways of the lungs, as with some other biopsy procedures.

To perform this test, the doctor numbs the skin with a local anesthetic, then inserts a very small needle between the ribs and into the lung tumor to withdraw a small tissue sample. Doctors use CT scan images to help guide the needle during the process.

You may need to hold your breath during the procedure so your lungs don’t move. You can usually return home the same day. After the biopsy, you may experience some discomfort, which can be treated with medication.

Bronchoscopy

Doctors may use bronchoscopy to view and remove tumor tissue in the airways. During this procedure, doctors insert a bronchoscope—a long, flexible tube with a camera—through the nose or mouth and into the airways. After the tumor is located, doctors thread surgical instruments, such as small forceps or needles, through the bronchoscope to take tissue or liquid samples. Sometimes doctors use fluoroscopy, an imaging technique that uses two-dimensional X-rays, to guide the bronchoscopy.

Bronchoscopy is done using sedation or general anesthesia. An anesthetic spray may be applied to your throat. After the sedation or anesthesia wears off, you can go home.

Endobronchial Ultrasound

Endobronchial ultrasound allows doctors to sample a lung tumor when it is next to an accessible airway.

In this procedure, a doctor inserts a bronchoscope with an ultrasound device on its end into the lungs’ airways. The ultrasound device uses sound waves to create pictures of the structures surrounding the airways on a computer monitor. Doctors often use this approach to locate and biopsy enlarged lymph nodes found on previous imaging tests.

Radial endobronchial ultrasound is a technology in which a tiny ultrasound probe is inserted through a catheter, or hollow tube, through the channel of a standard bronchoscope. This long probe can reach deeper into the lungs than standard endobronchial ultrasound. Doctors can move the probe back and forth in the airways deep within the lungs to create images of suspicious growths, which they can then sample using tools inserted through the scope.

Before either of these procedures, a doctor gives you a sedative or anesthesia to relax you and a local anesthetic to numb the throat. You can return home after the sedative or anesthesia wears off.

Electromagnetic Navigation Bronchoscopy

Electromagnetic navigation bronchoscopy, which resembles the global positioning system (GPS) in cars, can help doctors find lung tumors.

During the procedure, doctors place sensors on your chest and back, which creates an electromagnetic field. Then a probe or catheter with another sensor on its end is threaded into the lungs through a bronchoscope. Doctors use the electromagnetic field to track the position of the probe and bronchoscope on a detailed, three-dimensional CT scan image of the chest as they move through the lungs.

Using this guidance system, doctors can perform biopsies of tissue in distant areas of the lungs that are hard to reach using conventional bronchoscopy.

Doctors may use this technique to mark small lung tumors with blue dye so they can be easily located during surgery. Electromagnetic navigation bronchoscopy can also be used to place small “fiducial markers,” tiny wires that can be detected with imaging scans. These markers can guide targeted radiation therapy or stereotactic body radiation therapy, in which energy beams are used to destroy cancer cells.

This procedure requires general anesthesia. Doctors apply a local anesthetic to your throat beforehand. You can return home after the anesthesia wears off.

When small cell lung cancer has been diagnosed, doctors may conduct a number of tests to see whether the condition has spread.

Endoscopic Esophageal Ultrasound

Endoscopic esophageal ultrasound helps doctors determine whether cancer has spread to lymph nodes in the area. During this procedure, a doctor inserts an endoscope, a thin tube with a light and an ultrasound device on its end, through the mouth or nose and into the esophagus, the long muscular tube that runs from the mouth to the stomach. If a doctor detects swollen lymph nodes on the ultrasound, he or she can place a small needle through the endoscope to take a tissue sample.

You may receive a local anesthetic to numb the back of the throat and a sedative to help you relax during the procedure. You can return home after the anesthesia wears off.

Mediastinoscopy

Mediastinoscopy helps doctors determine whether the lung cancer has spread to lymph nodes in the center of the chest. During this procedure, a doctor makes a small incision in the neck and inserts a mediastinoscope, a thin tube that resembles an endoscope with a video camera on the end. It is placed in front of the trachea, where the surgeon can view a group of lymph nodes. The images appear on a computer monitor. The doctor inserts surgical tools through the scope to take tissue samples from these lymph nodes.

Mediastinoscopy requires general anesthesia. You may be required to stay in the hospital overnight so a doctor can monitor you and manage any discomfort.

Thoracoscopy

A thoracoscopy can help doctors determine whether lung cancer has spread to the pleural cavity. During this procedure, a surgeon places a thoracoscope, a thin tube with a video camera on its end, through a small incision between the ribs to view the pleural cavity and lining for signs of cancer. He or she inserts small surgical tools through the scope to take tissue samples.

Thoracoscopy can also be used to biopsy tumors on the outer parts of the lungs and area lymph nodes. Fluid in the pleural cavity may also be removed for evaluation.

The procedure requires general anesthesia, and you may need to stay in the hospital overnight so our doctors can monitor you and manage any discomfort.

MRI Scan

An MRI scan can help doctors determine whether small cell lung cancer has spread to the brain. This scan uses magnets, radio waves, and computers to create detailed, three-dimensional images of the body’s structures. MRI scans produce more detailed images of soft tissue, including the brain, than CT scans. Knowing how far the cancer has spread can help doctors develop a treatment plan.

Perlmutter Cancer Center researchers are part of the National Cancer Institute’s Early Detection Research Network, a group of scientists who are researching biomarkers, substances in the blood or tissue that can help them diagnose small cell lung cancer. Biomarkers may help doctors determine how aggressive the condition might be and which treatment may be most effective.