Glossary of Lung Cancer Terms | American Lung Association

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Glossary of Lung Cancer Terms

Find definitions of common lung cancer terminology.


Ablation therapies (a-BLAY-shun)
Treatment involving destruction or removal of diseased tissue.

Adenocarcinoma (A-deh-noh-KAR-sih-NOH-muh)
A form of non-small cell lung cancer often found in an outer area of the lung. It develops in the cells of epithelial tissues, which line the cavities and surfaces of the body and form glands.

Adjuvant therapy (A-joo-vunt THAYR-uh-pee)
Treatment given after the main type of treatment (usually surgery) to increase the chances of cure.

Advance directive (ad-VANS duh-REK-tiv)
A legal document that tells the doctor and family what a person wants for future medical care should the person later become unable to make decisions for him or herself.

Alternative Therapy
Alternative therapy is used in place of standard medical treatments.

Anaplastic Lymphoma Kinase (ALK) gene rearrangement (A-nuh-PLAS-tik lim-FOH-muh KY-nays)
An ALK mutation is a gene rearrangement in a gene called anaplastic lymphoma kinase. This gene rearrangement mutation joins another gene to ALK and "turns it on," telling cancer cells to multiply.

Anti-angiogenesis therapy (an-jee-o-JEN-uh-sis)
Angiogenesis is when cancerous tumors create new blood vessels, which helps them grow and spread. This therapy uses drugs to prevent the growth of new blood vessels to tumors.

Alveoli (al-vee-oh-lie)
Very small air sacs at the end of each bronchiole.

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A molecule found in the body that is a sign of a normal or abnormal process, or of a condition or disease. Biomarker testing can provide important information about treatment options.

Biopsy (BY-op-see)
The removal of a small piece of tissue for laboratory examination.

Bone scan (bone skan)
A small, safe amount of radioactive substance is put into the vein. This substance builds up in areas of bone that may not be normal because of cancer. These areas show up as dense, gray to black areas, called "hot spots." These areas may indicate cancer.

Brachytherapy (internal or implant radiation therapy) (BRAY-kee-THAYR-uh-pee)
Sealed radioactive material is placed directly into or near the tumor.

BRAF V600E is a specific mutation in the BRAF gene. It makes a protein that helps drive cancer growth.

Bronchoscopy (bron-KOS-koh-pee)
A lighted, flexible tube (called a bronchoscope) is passed through the mouth or nose and into the large airways of the lungs. This test can help the doctor see tumors, or it can be used to take samples of tissue or fluids to see if cancer cells are present. Learn more about bronchoscopy.

Bronchus (BRON-kus)
Either of the two major branches of the tracheas (windpipe) that lead to the lungs. The trachea divides to form the right and left main bronchi (pleural of bronchus) which lead to each of the lungs.

Bronchioles (brong-kee-oles)
The smallest airways branching off from each bronchus.

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Cancer survival rates
The percentage of people who survive a certain type of cancer for a specific amount of time. Cancer statistics often use an overall five-year survival rate. If the overall five-year survival rate of a certain cancer is 80 percent, that means that of all people diagnosed with that cancer, 80 of every 100 were living five years after diagnosis.

Capillaries (cap-ill-er-ees)
Very small blood vessels where oxygen and carbon dioxide are exchanged.

Carcinoma in situ (car-sin-O-ma in sy-too)
Cancer cells are found only in the innermost lining of the lung. The tumor has not grown through the lining.

Cellular Pathways
Complex systems of proteins and other molecules that, when turned on, change how the cells act. Sometimes these pathways tell the cell to do something abnormal, which leads to disease.

Cilia (sih-lee-uh)
Tiny hairs that sweep fluids and foreign particles out of the airway so that they stay out of the lungs.

Complementary therapy (KOM-pleh-MEN-tuh-ree)
Non-standard treatment used in addition to standard treatment.

Complete response, apparently cancer free or No Evidence of Disease (NED)
On an imaging scan, the tumor looks like it is completely gone because of treatment.

Cryotherapy (KRY-oh-THAYR-uh-pee)
Use of extreme cold to kill cancer cells

CT scan (computed tomography)
A CT (or CAT) scan is a special kind of x-ray that takes many pictures as you lie on a table that slides in and out of the machine. A computer then combines these pictures into a detailed picture of a slice of your body. Learn more about CT scan.

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Diaphragm (DY-uh-fram)
The strong wall of muscle that separates the chest cavity from the abdominal cavity. By moving downward, it creates suction in the chest to draw in air and expand the lungs.

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Endobronchial ultrasound (en-doh BRON-kee-ul)
For endobronchial ultrasound, a bronchoscope (a thin, lighted, flexible tube) is fitted with an ultrasound device (a device that uses sound waves to make pictures of the inside of your body) at its tip. It is passed down into the windpipe to look at nearby lymph nodes and other structures in the chest. This is done with numbing medicine (local anesthesia) and light sedation. A hollow needle can be passed through the bronchoscope and guided by ultrasound into an area of concern to take biopsy samples. Learn more about EBUS.

A chemical substance in the body belonging to a group resembling organic chemicals found in cannabis.

Endoscopic esophageal ultrasound (en-doh-SKAH-pik ee-SAH-fuh-JEE-ul)
This test is much like an endobronchial ultrasound, except that an endoscope (a lighted, flexible tube) is used. It is passed down the throat and into the esophagus.

Epidermal growth factor receptor (EGFR) inhibitors (eh-pih-DER-mul grothe FAK-ter reh-SEP-ter in-HIH-bih-ter)
Drugs that block receptors of proteins that aid in cancer cell growth.

Epidermal growth factor receptor (EGFR) mutation (eh-pih-DER-mul grothe FAK-ter reh-SEP-ter myoo-TAY-shun)
EGFR stands for epithelial growth factor receptor, a protein that is present on the surface of both normal cells and cancer cells such as lung cancer cells. A mutation of this protein causes cancer.

External beam radiation (external beam)
Doses of radiation are aimed at lungs or surrounding areas.

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Fine needle biopsy (FNA)
A long, thin (fine) needle is used to remove a sample of cells from the area that may be cancer. The sample is examined in the lab to see if it contains cancer cells.

First-line therapy
Initial cancer treatment

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Guidelines are created by experts in the field. They review all of the science and create a grading system for recommending treatments. Guidelines help doctors present the best treatment options for your cancer.

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Hospice (HOS-pis)
Refers to a system of care for dying people and their families. Most hospice care is administered at home, but some hospice facilities exist. Hospice care is recommended when life expectancy is six months or less and treatment of the cancer has been discontinued.

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Integrated medicine
The combined use of standard and complementary therapy.

Intensity Modulated Radiation Therapy (IMRT) (in-TEN-sih-tee-MAH-juh-LAY-tid RAY-dee-AY-shun THAYR-uh-pee)
Radiation beams are shaped to match the tumor. The intensity of the treatment can be changed throughout the session.

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A mutation on the KRAS gene can disrupt the K-Ras protein, which controls cell growth and death.

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Large Cell Carcinoma (...KAR-sih-NOH-muh)
A form of non-small cell lung cancer that can occur in any part of the lung and tends to grow and spread faster than adenocarcinoma or squamous cell carcinoma.

Late Effect
A side effect from treatment that occurs months or years after a diagnosis of cancer.

The right lung is divided into three lobes, or sections. The left lung is divided into two lobes. Each lobe is like a balloon filled with sponge-like tissue. Air moves in and out through one opening—a branch of the bronchial tube.

Lobectomy (loh-BEK-toh-mee)
A lobe of the lung is removed. Learn more about lobectomy.

Lymph (limf)
An immune system fluid that helps collect unwanted materials for removal from the body.

Lymph nodes (limf nodes)
Small kidney bean-shaped immune system organs distributed all over the body.

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Malignant (muh-LIG-nunt)
A term used to refer to cancerous cells or tumors. Malignant cells are abnormal and grow uncontrollably. They may invade and destroy other parts of the body.

Mediastinoscopy and mediastinotomy (MEE-dee-uh-sty-NOS-koh-pee)
Both of these tests let the surgeon look at and take samples of lymph nodes in the area between the lungs (this area is called the mediastinum).

Metastasis (meh-TAS-tuh-sis)
The spread of cancer from its primary site to other places in the body.

Monoclonal antibodies (MAH-noh-KLOH-nul AN-tee-BAH-dee)
Proteins made in a laboratory that can attach to tumor cells and tell the cell what to do. There are many types of monoclonal antibodies, each made to find one substance. They can be used alone or they can destroy the cell by carrying toxins to the tumor.

MRI scan (magnetic resonance imaging) (mag-NEH-tik REH-zuh-nunts IH-muh-jing)
MRI scans give detailed pictures of soft tissues in the body using radio waves and strong magnets. MRI scans are useful in finding lung cancer that has spread to the brain or spinal cord.

Mucus (MYOO-kus)
A thick, slippery fluid made by the membranes that line certain organs of the body, including the lungs. It collects unwanted matter like dust and germs.

Multi-modality or combined modality
Treatment using a combination of therapies.

Mutation (myoo-TAY-shun)
A permanent change in the DNA sequence of a gene.

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Neoadjuvant therapy (NEE-oh-A-joo-vant THAYR-uh-pee)
Treatment given before the main type of treatment to increase the chances of successful response.

Non-Small Cell Lung Cancer
About 85 to 90 percent of lung cancers are non-small cell lung cancer (NSCLC). There are three main subtypes of NSCLC, which look different under a microscope but are treated similarly. The subtypes are adenocarcinoma, squamous cell carcinoma and large cell carcinoma.

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Occult stage non-small cell lung cancer (uh-KULT)
Cancer cells are found in sputum (mucus coughed up from the lungs), but no tumor can be found in the lung by imaging tests or bronchoscopy, or the tumor is too small to be biopsied.

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Palliative care (PA-lee-uh-tiv kayr)
Care aimed at making the patient more comfortable and improving quality of life. Hospice care always includes palliative care, but palliative care can be administered at any stage of a disease.

Palliative therapy (PA-lee-uh-tiv)
Treatment to relieve symptoms, but not treat the disease.

Partial Response
The tumor has shrunk in size by at least 30 percent.

Pathologist (puh-THAH-loh-jist)
A doctor who identifies diseases by studying cells and tissues under a microscope.

PD-L1 is a protein expressed by cancer cells that keep the immune system from attacking the cancer. The PD-L1 levels in your tumor may help predict whether or not immunotherapy is right for you.

PET scan (positron emission tomography)
For a PET scan, a form of radioactive sugar is injected into the blood. Cancer cells in the body absorb large amounts of the sugar. A special camera can then spot the radioactivity. This test can help show whether the cancer has spread to the lymph nodes or other parts of the body.

Photodynamic therapy (PDT) (FOH-toh-dy-NA-mik THAYR-uh-pee)
A special chemical is injected into the blood stream that stays in cancer cells longer than regular cells. A laser activates the chemical in the cancer cells and kills them.

Pleura (PLOOR-uh)
The pleura are the two membranes that surround each lobe of the lungs and separate the lungs from the chest wall.

Pneumonectomy (NOO-moh-NEK-toh-mee)
The removal of the entire lung affected by cancer.

Power of attorney
A written document often used when someone wants another adult to make decisions on their behalf.

Prognosis (prog-NO-sis)
A prediction of the probable course and outcome of a disease.

Progressive disease
The tumor continues to grow in spite of treatment.

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Radiofrequency ablation (RAY-dee-oh-FREE-kwen-see a-BLAY-shun)
Uses thermal (heat) energy to kill cells.

ROS-1 is an enzyme that is coded by the ROS-1 gene. A mutation leads to a rearrangement of the gene which causes the cancer to grow.

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Second-line therapy
Treatment that follows if the first is not successful.

Sleeve resection (...ree-SEK-shun)
Surgery to remove a lung tumor in a lobe of the lung and a part of the main bronchus (airway). The ends of the bronchus are rejoined attaching any remaining lobes to the bronchus. This surgery is done to save part of the lung. Also called sleeve lobectomy.

Small Cell Lung Cancer
About 10 to 15 percent of all lung cancers are small cell lung cancer (SCLC), named for the small cells that make up these cancers. SCLC often starts in the bronchi near the center of the chest, and it tends to spread widely through the body early in the course of the disease.

Sputum cytology (SPYOO-tum sy-TAH-loh-jee)
A sample of mucus you cough up from the lungs (called sputum or phlegm) is examined under a microscope to see if cancer cells are present.

Squamous Cell Carcinoma (SKWAY-mus sel KAR-sih-NOH-muh)
A form of non-small cell lung cancer usually found in the center of the lung next to an air tube (bronchus).

Stable Disease
The tumor's size did not change much.

Stereotactic Body Radiation Therapy (SBRT)/ Stereotactic Ablative Radiotherapy (SABR)
Stereotactic Body Radiation Therapy (SBRT), also known as Stereotactic Ablative Radiotherapy (SABR) uses a very high dose of radiation delivered very accurately to tumors in the lung or other organs while limiting the dose to the surrounding organs.

Stereotactic Radiosurgery (SRS) (STAYR-ee-oh-TAK-tik RAY-dee-oh-SER-juh-ree)
Uses a very high dose of radiation delivered very accurately to lung cancer tumors that have spread to the central nervous system (the brain and spinal cord).

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More than half of lung cancer patients with an EGFR mutation will develop a second mutation called T790M that causes resistance to drugs that treat EGFR.

Thoracentesis (THOR-uh-sen-TEE-sis)
This test is done to check whether fluid around the lungs is caused by cancer or by some other medical problem. A needle is placed between the ribs to drain the fluid. The fluid is checked for cancer cells.

Thoracoscopy (THOR-uh-KOS-koh-pee)
A small cut is made in the chest. The surgeon 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. The surgeon can see small tumors on the lung or lining of the chest wall and can take out pieces of tissue to be looked at under the microscope. Thoracoscopy can also be used as part of the treatment to remove part of a lung in some early-stage lung cancers.

Thoracotomy (THOR-uh-KAH-toh-mee)
An incision is made across the back and side of the chest. The ribs are spread apart so the surgeon can access the lung. Learn more about thoractomy.

A tumor is an abnormal growth of body tissue.

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Vaccine Therapy
Tumor cells are used to develop a vaccine and then injected into the patient. The vaccine aims to make the immune system recognize the tumor as foreign and attack the cancer cells.

Video-assisted thoracic surgery (VATS)
A new type of surgery that allows surgeons to make very small incisions to view the inside of the chest cavity and remove cancer.

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Wedge resection (wej ree-SEK-shun)
Surgery to remove a small portion of the lung along with healthy tissue that surrounds the lung.

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An X-ray produces pictures of the structures inside your body—particularly your bones.

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Approved by Scientific and Medical Editorial Review Panel. Last reviewed December 18, 2017.

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